Bump opensafely-core/setup-action from 1 to 1.6.1

Bumps [opensafely-core/setup-action](https://github.com/opensafely-core/setup-action) from 1 to 1.6.1.
- [Release notes](https://github.com/opensafely-core/setup-action/releases)
- [Commits](opensafely-core/setup-action@v1...v1.6.1)

---
updated-dependencies:
- dependency-name: opensafely-core/setup-action
  dependency-version: 1.6.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/check_links.yml

@@ -19,7 +19,7 @@ jobs:
         uses: actions/checkout@v7.0.0
 
       - name: Install Python and just
-        uses: opensafely-core/setup-action@v1
+        uses: opensafely-core/setup-action@v1.6.1
         with:
           install-just: true
           python-version: '3.11'

.github/workflows/check_vale.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/checkout@v7.0.0
 
       - name: Install just
-        uses: opensafely-core/setup-action@v1
+        uses: opensafely-core/setup-action@v1.6.1
         with:
           install-just: true
 

.github/workflows/pages-deployment.yml

@@ -21,7 +21,7 @@ jobs:
         uses: actions/checkout@v7.0.0
 
       - name: Install Python and just
-        uses: opensafely-core/setup-action@v1
+        uses: opensafely-core/setup-action@v1.6.1
         with:
           install-just: true
           python-version: '3.11'