support warpbuild cache provider (#247)

Author: stegaBOB

README.md

@@ -82,7 +82,7 @@ sensible defaults.
     lookup-only: ""
 
     # Specifies what to use as the backend providing cache
-    # Can be set to either "github" or "buildjet"
+    # Can be set to "github", "buildjet", or "warpbuild"
     # default: "github"
     cache-provider: ""
 

action.yml

@@ -41,7 +41,7 @@ inputs:
     required: false
     default: "true"
   cache-provider:
-    description: "Determines which provider to use for caching. Options are github or buildjet, defaults to github."
+    description: "Determines which provider to use for caching. Options are github, buildjet, or warpbuild. Defaults to github."
     required: false
     default: "github"
   cache-bin: