Bump esphome/build-action from 1.1 to 1.2.1 (klaasnicolaas#116)

Bumps [esphome/build-action](https://github.com/esphome/build-action) from 1.1 to 1.2.1.
- [Release notes](https://github.com/esphome/build-action/releases)
- [Commits](esphome/build-action@v1.1...v1.2.1)

---
updated-dependencies:
- dependency-name: esphome/build-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yaml

@@ -13,6 +13,6 @@ jobs:
       - name: ⤵️ Check out files from GitHub
         uses: actions/checkout@v2
       - name: Test firmware build
-        uses: esphome/build-action@v1.1
+        uses: esphome/build-action@v1.2.1
         with:
           yaml_file: home_assistant_glow.yaml