Fix CircleCI; Bump Go version in CircleCI

.circleci/config.yml

@@ -8,61 +8,61 @@ workflows:
       - lint:
           requires:
             - checkout_code
-          go_version: "1.12"
+          go_version: "1.13"
           vips_version: "8.8"
       - build:
-          name: go1.12_vips8.8
+          name: go1.13_vips8.8
           requires:
             - checkout_code
-          go_version: "1.12"
+          go_version: "1.13"
           vips_version: "8.8"
       - build:
-          name: go1.12_vips8.7
+          name: go1.13_vips8.7
           requires:
             - checkout_code
-          go_version: "1.12"
+          go_version: "1.13"
           vips_version: "8.7"
       - build:
-          name: go1.12_vips8.6
+          name: go1.13_vips8.6
           requires:
             - checkout_code
-          go_version: "1.12"
+          go_version: "1.13"
           vips_version: "8.6"
       - build:
-          name: go1.11_vips8.8
+          name: go1.12_vips8.8
           requires:
             - checkout_code
-          go_version: "1.11"
+          go_version: "1.12"
           vips_version: "8.8"
       - build:
-          name: go1.11_vips8.7
+          name: go1.12_vips8.7
           requires:
             - checkout_code
-          go_version: "1.11"
+          go_version: "1.12"
           vips_version: "8.7"
       - build:
-          name: go1.11_vips8.6
+          name: go1.12_vips8.6
           requires:
             - checkout_code
-          go_version: "1.11"
+          go_version: "1.12"
           vips_version: "8.6"
       - build:
-          name: go1.10_vips8.8
+          name: go1.11_vips8.8
           requires:
             - checkout_code
-          go_version: "1.10"
+          go_version: "1.11"
           vips_version: "8.8"
       - build:
-          name: go1.10_vips8.7
+          name: go1.11_vips8.7
           requires:
             - checkout_code
-          go_version: "1.10"
+          go_version: "1.11"
           vips_version: "8.7"
       - build:
-          name: go1.10_vips8.6
+          name: go1.11_vips8.6
           requires:
             - checkout_code
-          go_version: "1.10"
+          go_version: "1.11"
           vips_version: "8.6"
 
 executors:
@@ -95,6 +95,7 @@ commands:
           command: |
             gvm install go<< parameters.go_version >> -B
             gvm use go<< parameters.go_version >> --default
+            echo 'export GO111MODULE=on' >> $BASH_ENV
             echo 'export GOPATH=/go' >> $BASH_ENV
             echo 'export PATH="$PATH:$(go env GOPATH)/bin"' >> $BASH_ENV
             echo 'export CGO_LDFLAGS_ALLOW="-s|-w"' >> $BASH_ENV