Bump Workiva/gha-dart-oss from 0.1.5 to 0.1.6 in the gha group

Bumps the gha group with 1 update: [Workiva/gha-dart-oss](https://github.com/workiva/gha-dart-oss).


Updates `Workiva/gha-dart-oss` from 0.1.5 to 0.1.6
- [Release notes](https://github.com/workiva/gha-dart-oss/releases)
- [Commits](Workiva/gha-dart-oss@v0.1.5...v0.1.6)

---
updated-dependencies:
- dependency-name: Workiva/gha-dart-oss
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: gha
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci.yaml

@@ -10,15 +10,15 @@ on:
 
 jobs:
   build:
-    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].5
+    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].6
 
   checks:
-    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].5
+    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].6
 
   test-unit:
     strategy:
       matrix:
         sdk: [ 2.19.6, stable ]
-    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].5
+    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].6
     with:
       sdk: ${{ matrix.sdk }}

.github/workflows/publish.yaml

@@ -12,4 +12,4 @@ permissions:
 
 jobs:
   publish:
-    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].5
+    uses: Workiva/gha-dart-oss/.github/workflows/[email protected].6