Enable manual triggering of Merge Criteria workflow (#379)

Closes #380

.github/workflows/merge-criteria.yml

@@ -4,6 +4,12 @@ on:
   pull_request:
   push:
     branches: main
+  workflow_dispatch:
+    inputs:
+      commit_sha:
+        description: 'Commit SHA to build'
+        required: false
+        type: string
 
 jobs:
   generate_matrix:
@@ -13,6 +19,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.inputs.commit_sha || github.event.pull_request.head.sha || github.sha }}
 
       - name: Get changed directories
         id: changed-files
@@ -36,8 +44,9 @@ jobs:
         run: |
           contains_dot=$(echo '${{ steps.changed-files.outputs.all_changed_files }}' | jq 'map(select(. == ".")) | length')
           contains_dotgithub=$(echo '${{ steps.changed-files.outputs.all_changed_files }}' | jq 'map(select(. == ".github")) | length')
+          is_manual_trigger=$(echo '${{ github.event.inputs.commit_sha }}')
 
-          if [[ "${GITHUB_REF}" == "refs/heads/main" || $contains_dot -gt 0 || $contains_dotgithub -gt 0 ]]; then
+          if [[ -z "$is_manual_trigger" || "${GITHUB_REF}" == "refs/heads/main" || $contains_dot -gt 0 || $contains_dotgithub -gt 0 ]]; then
             filtered_array='["flight_computer","ground_station","telemetry"]'
           else
             filtered_array='${{ steps.changed-files.outputs.all_changed_files }}'