chore: change workflow input labels for clarity

The workflow already worked on commit SHAs and branch names, but the
input only listed tags. I've updated the label to make it clear.

Author: dimi-cb

.github/workflows/publish.yaml

@@ -7,8 +7,8 @@ on:
         description: 'Optional version to use (bypasses version bump and git commits if provided)'
         required: false
         default: ""
-      mfd-tag:
-        description: 'The MFD tag to use for API docs'
+      mfd-ref:
+        description: 'The MFD ref (branch, tag, or SHA) to use for API docs'
         required: false
         default: ""
 
@@ -63,12 +63,12 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ steps.generate-token.outputs.token }}
         run: |
-          MFD_TAG='${{ inputs.mfd-tag }}'
-          if [[ -z "${MFD_TAG}" ]]; then
-            MFD_TAG=$(gh api /repos/cloudbeds/mfd/releases/latest | jq -r '.tag_name')
+          MFD_REF='${{ inputs.mfd-ref }}'
+          if [[ -z "${MFD_REF}" ]]; then
+            MFD_REF=$(gh api /repos/cloudbeds/mfd/releases/latest | jq -r '.tag_name')
           fi
-          echo "Latest MFD tag: $MFD_TAG"
-          gh api /repos/cloudbeds/mfd/tarball/$MFD_TAG | tar --strip-components=1 --wildcards -zxf - '*/public_accessa/api'
+          echo "Using MFD ref: $MFD_REF"
+          gh api /repos/cloudbeds/mfd/tarball/$MFD_REF | tar --strip-components=1 --wildcards -zxf - '*/public_accessa/api'
 
       - name: Get next version
         run: |