Cache-on-failure support (#22)

action.yml

@@ -14,6 +14,9 @@ inputs:
   target-dir:
     description: "The target dir that should be cleaned and persisted, defaults to `./target`"
     required: false
+  cache-on-failure:
+    description: "Cache even if the build fails. Defaults to false"
+    required: false
 outputs:
   cache-hit:
     description: "A boolean value that indicates an exact match was found"
@@ -21,7 +24,7 @@ runs:
   using: "node12"
   main: "dist/restore/index.js"
   post: "dist/save/index.js"
-  post-if: "success()"
+  post-if: "success() || env.CACHE_ON_FAILURE == 'true'"
 branding:
   icon: "archive"
   color: "gray-dark"