Close resource streams for mixin configs. (FabricMC#185)

* Close resource streams for mixin configs.

* Close resource streams for mixin configs.

* Simplify

* Remove Unneeded changes & Import

---------

Co-authored-by: cputnam-a11y <unknown@cputnam-a11y.github.io>

Author: cputnam-a11y

src/main/java/org/spongepowered/asm/mixin/transformer/MixinConfig.java

@@ -1394,9 +1394,11 @@ static Config create(String configFile, MixinEnvironment outer, IMixinConfigSour
             if (resource == null) {
                 throw new IllegalArgumentException(String.format("The specified resource '%s' was invalid or could not be read", configFile));
             }
-            MixinConfig config = new Gson().fromJson(new InputStreamReader(resource), MixinConfig.class);
-            if (config.onLoad(service, configFile, outer, source)) {
-                return config.getHandle();
+            try (InputStreamReader reader = new InputStreamReader(resource)) {
+                MixinConfig config = new Gson().fromJson(reader, MixinConfig.class);
+                if (config.onLoad(service, configFile, outer, source)) {
+                    return config.getHandle();
+                }
             }
             return null;
         } catch (IllegalArgumentException ex) {