try allow build from commit hash

.github/workflows/kcpp-build-release-win-full-cu12.yaml

@@ -1,6 +1,13 @@
 name: Koboldcpp Windows Full Binaries CUDA 12
 
-on: workflow_dispatch
+on:
+  workflow_dispatch:
+    inputs:
+      commit_hash:
+        description: 'Optional commit hash to build from'
+        required: false
+        default: ''
+
 env:
   BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
 
@@ -12,7 +19,11 @@ jobs:
         id: checkout
         uses: actions/checkout@v3
         with:
-          ref: ${{ github.head_ref || github.ref_name }}
+          ref: ${{ inputs.commit_hash != '' && inputs.commit_hash || github.head_ref || github.ref_name }}
+
+      - name: Show Commit Used
+        run: |
+          echo "Building from ref: ${{ inputs.commit_hash != '' && inputs.commit_hash || github.head_ref || github.ref_name }}"
 
       - name: Get Python
         uses: actions/setup-python@v2