Allow optional code checkout

Allow disabling the code checkout to allow caller workflows to control
the checkout reference used when determining product version metadata.

Signed-off-by: Ryan Cragun <me@ryan.ec>

action.yml

@@ -2,12 +2,18 @@ name: set-product-version
 author: Release Engineering <rel-eng@hashicorp.com>
 description: Automates setting product version
 
+inputs:
+  checkout:
+    description: |
+      Check out the code repository. Can be disabled if checkout is handled by the caller workflow.
+    default: true
 
 runs:
   using: composite
 
   steps:
-    - uses: actions/checkout@v3
+    - if: inputs.checkout == 'true'
+      uses: actions/checkout@v3
     - name: Check if Version File Exists
       shell: bash
       env: