Add a restore-only option to support pulling without saving a cache entry

src/save.ts

@@ -18,6 +18,13 @@ async function run(): Promise<void> {
             return;
         }
 
+        if (core.getInput(Inputs.RestoreOnly) === "true") {
+            core.info(
+                "Cache action configured for restore-only, skipping save step"
+            );
+            return;
+        }
+
         const state = utils.getCacheState();
 
         // Inputs are re-evaluted before the post action, so we want the original key used for restore