Added a script to change the labels on github issues which match the search (#25828)

For instance:

    ./dev-tools/github_relabel.pl --state=open --labels=v5.5.1 --remove=v5.5.1 --add=v5.5.2

dev-tools/github_relabel.pl

@@ -0,0 +1,184 @@
+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+
+use HTTP::Tiny;
+use IO::Socket::SSL 1.52;
+use utf8;
+use Getopt::Long;
+
+my $Base_URL  = "https://api.github.com/repos/";
+my $User_Repo = 'elastic/elasticsearch/';
+my $Issue_URL = "https://github.com/${User_Repo}issues";
+use JSON();
+use URI();
+use URI::Escape qw(uri_escape_utf8);
+
+our $json = JSON->new->utf8(1);
+our $http = HTTP::Tiny->new(
+    default_headers => {
+        Accept        => "application/vnd.github.v3+json",
+        Authorization => load_github_key()
+    }
+);
+
+my %Opts = ( state => 'open' );
+
+GetOptions(
+    \%Opts,    #
+    'state=s', 'labels=s', 'add=s', 'remove=s'
+) || exit usage();
+
+die usage('--state must be one of open|all|closed')
+    unless $Opts{state} =~ /^(open|all|closed)$/;
+
+die usage('--labels is required') unless $Opts{labels};
+die usage('Either --add or --remove is required')
+    unless $Opts{add} || $Opts{remove};
+
+relabel();
+
+#===================================
+sub relabel {
+#===================================
+    my @remove = split /,/, ( $Opts{remove} || '' );
+    my @add    = split /,/, ( $Opts{add}    || '' );
+    my $add_json = $json->encode( \@add );
+    my $url      = URI->new( $Base_URL . $User_Repo . 'issues' );
+    $url->query_form(
+        state    => $Opts{state},
+        labels   => $Opts{labels},
+        per_page => 100
+    );
+
+    my $spool = Spool->new($url);
+    while ( my $issue = $spool->next ) {
+        my $id = $issue->{number};
+        print "$Issue_URL/$id\n";
+        if (@add) {
+            add_label( $id, $add_json );
+        }
+        for (@remove) {
+            remove_label( $id, $_ );
+        }
+    }
+    print "Done\n";
+}
+
+#===================================
+sub add_label {
+#===================================
+    my ( $id, $json ) = @_;
+    my $response = $http->post(
+        $Base_URL . $User_Repo . "issues/$id/labels",
+        {   content => $json,
+            headers => { "Content-Type" => "application/json; charset=utf-8" }
+        }
+    );
+
+    die "$response->{status} $response->{reason}\n"
+        unless $response->{success};
+
+}
+
+#===================================
+sub remove_label {
+#===================================
+    my ( $id, $name ) = @_;
+    my $url
+        = $Base_URL
+        . $User_Repo
+        . "issues/$id/labels/"
+        . uri_escape_utf8($name);
+    my $response = $http->delete($url);
+
+    die "$response->{status} $response->{reason}\n"
+        unless $response->{success};
+
+}
+
+#===================================
+sub load_github_key {
+#===================================
+    my ($file) = glob("~/.github_auth");
+    unless ( -e $file ) {
+        warn "File ~/.github_auth doesn't exist - using anonymous API. "
+            . "Generate a Personal Access Token at https://github.com/settings/applications\n";
+        return '';
+    }
+    open my $fh, $file or die "Couldn't open $file: $!";
+    my ($key) = <$fh> || die "Couldn't read $file: $!";
+    $key =~ s/^\s+//;
+    $key =~ s/\s+$//;
+    die "Invalid GitHub key: $key"
+        unless $key =~ /^[0-9a-f]{40}$/;
+    return "token $key";
+
+}
+
+#===================================
+sub usage {
+#===================================
+    my $msg = shift || '';
+
+    if ($msg) {
+        $msg = "\nERROR: $msg\n\n";
+    }
+    return $msg . <<"USAGE";
+$0 --state=open|closed|all --labels=foo,bar --add=new1,new2 --remove=old1,old2
+
+USAGE
+
+}
+
+package Spool;
+
+use strict;
+use warnings;
+
+#===================================
+sub new {
+#===================================
+    my $class = shift;
+    my $url   = shift;
+    return bless {
+        url    => $url,
+        buffer => []
+        },
+        $class;
+}
+
+#===================================
+sub next {
+#===================================
+    my $self = shift;
+    if ( @{ $self->{buffer} } == 0 ) {
+        $self->refill;
+    }
+    return shift @{ $self->{buffer} };
+}
+
+#===================================
+sub refill {
+#===================================
+    my $self = shift;
+    return unless $self->{url};
+    my $response = $http->get( $self->{url} );
+    die "$response->{status} $response->{reason}\n"
+        unless $response->{success};
+
+    $self->{url} = '';
+
+    if ( my $link = $response->{headers}{link} ) {
+        my @links = ref $link eq 'ARRAY' ? @$link : $link;
+        for ($link) {
+            next unless $link =~ /<([^>]+)>; rel="next"/;
+            $self->{url} = $1;
+            last;
+        }
+    }
+
+    push @{ $self->{buffer} }, @{ $json->decode( $response->{content} ) };
+
+}