chore(deps): update earthly/earthly docker tag to v0.8.15 (#33)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/continuous-integration.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Download Earthly v0.8.6.
         uses: earthly/actions-setup@v1
         with:
-          version: v0.8.6
+          version: v0.8.15
       - name: Checkout code.
         uses: actions/checkout@v4
       - name: Compile.

.github/workflows/conventional-commits.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Download Earthly v0.8.6.
         uses: earthly/actions-setup@v1
         with:
-          version: v0.8.6
+          version: v0.8.15
       - name: Checkout code.
         uses: actions/checkout@v4
         with:

.github/workflows/git-history.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Download Earthly v0.8.6.
         uses: earthly/actions-setup@v1
         with:
-          version: v0.8.6
+          version: v0.8.15
       - name: Checkout code.
         uses: actions/checkout@v4
         with:

.github/workflows/github-actions-workflows.yml

@@ -14,7 +14,7 @@ jobs:
       - name: Download Earthly v0.8.6.
         uses: earthly/actions-setup@v1
         with:
-          version: v0.8.6
+          version: v0.8.15
       - name: Checkout code.
         uses: actions/checkout@v4
       - name: Check GitHub Actions workflows linting.
@@ -26,7 +26,7 @@ jobs:
       - name: Download Earthly v0.8.6.
         uses: earthly/actions-setup@v1
         with:
-          version: v0.8.6
+          version: v0.8.15
       - name: Checkout code.
         uses: actions/checkout@v4
       - name: Check formatting.