github/workflows: Fetch full history for mpremote workflow.

Instead of doing the shallow checkout followed by an unshallow-with-tags,
just set fetch-depth=0 to get the full history to start with.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

.github/workflows/mpremote.yml

@@ -13,11 +13,9 @@ jobs:
     steps:
     - uses: actions/checkout@v3
       with:
-        # Version is determined from git,
-        # should be deep enough to get to latest tag
-        fetch-depth: '1000'
-    - run: |
-        git fetch --prune --unshallow --tags
+        # Setting this to zero means fetch all history and tags,
+        # which hatch-vcs can use to discover the version tag.
+        fetch-depth: 0
     - uses: actions/setup-python@v4
     - name: Install build tools
       run: pip install build