fix(docs): typo source url encryption (#971)

Could not find it in the sourcecode, since this is part of the pro version. I'm assuming the typo is just in the docs and not in source code. Someone with access to Pro should verify this

docs/configuration.md

@@ -81,7 +81,7 @@ You can also specify a secret key to enable authorization with the HTTP `Authori
 
 If you don't want to reveal your source URLs, you can encrypt them with the AES-CBC algorithm:
 
-* `IMGPROXY_SOURCE_URL_ENCRYPRION_KEY`: hex-encoded key used for source URL encryption. Default: blank
+* `IMGPROXY_SOURCE_URL_ENCRYPTION_KEY`: hex-encoded key used for source URL encryption. Default: blank
 
 **📝Note:** Read more about source URL encryption in the [encrypting the source URL guide](encrypting_the_source_url.md).
 

docs/encrypting_the_source_url.md

@@ -6,7 +6,7 @@ If you don't want to reveal your source URLs, you can encrypt them with the AES-
 
 The only thing needed for source URL encryption is a key:
 
-* `IMGPROXY_SOURCE_URL_ENCRYPRION_KEY`: hex-encoded key used for source URL encryption. Default: blank
+* `IMGPROXY_SOURCE_URL_ENCRYPTION_KEY`: hex-encoded key used for source URL encryption. Default: blank
 
 The key should be either 16, 24, or 32 bytes long for AES-128-CBC, AES-192-CBC, or AES-256-CBC, respectively.
 
@@ -48,7 +48,7 @@ Before we start, we need an encryption key. We will use the AES-256-CBC algorith
 Run imgproxy using this encryption key, like so:
 
 ```bash
-IMGPROXY_SOURCE_URL_ENCRYPRION_KEY="1eb5b0e971ad7f45324c1bb15c947cb207c43152fa5c6c7f35c4f36e0c18e0f1" imgproxy
+IMGPROXY_SOURCE_URL_ENCRYPTION_KEY="1eb5b0e971ad7f45324c1bb15c947cb207c43152fa5c6c7f35c4f36e0c18e0f1" imgproxy
 ```
 
 Next, assume that you have the following source URL: