Allow uppercase environment variable creation

The current behaviour was to force all variable names
to lowercase which was resulting in the wrong behaviour on POST.

Instead, just force lowercase when comparing with existing variables.

Signed-off-by: Kyle Harding <[email protected]>

lib/plugins/environments.js

@@ -10,11 +10,7 @@ module.exports = class Environments extends Diffable {
       // Force all names to lowercase to avoid comparison issues.
       this.entries.forEach((environment) => {
         environment.name = environment.name.toLowerCase()
-        if (environment.variables) {
-          environment.variables.forEach((variable) => {
-            variable.name = variable.name.toLowerCase()
-          })
-        }
+        // Do not force variables to lowercase as they are case-sensitive on create (POST).
       })
     }
   }
@@ -297,11 +293,11 @@ module.exports = class Environments extends Diffable {
 
       for (const variable of attrs.variables) {
         const existingVariable = existingVariables.find(
-          (_var) => _var.name === variable.name
+          (_var) => _var.name === variable.name.toLowerCase()
         )
         if (existingVariable) {
           existingVariables = existingVariables.filter(
-            (_var) => _var.name === variable.name
+            (_var) => _var.name === variable.name.toLowerCase()
           )
           if (existingVariable.value !== variable.value) {
             await this.github.request(