Bump GitHub Actions dependencies (#13)

Updates actions/checkout, actions/setup-node, and actions/setup-python to their current v7 releases after all repository checks passed.

.github/workflows/ci.yml

@@ -20,8 +20,8 @@ jobs:
       run:
         working-directory: backend
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
         with:
           node-version: 20
           cache: npm
@@ -38,8 +38,8 @@ jobs:
       run:
         working-directory: frontend
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
         with:
           node-version: 20
           cache: npm
@@ -53,8 +53,8 @@ jobs:
     name: Workers and Compose
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v7
+      - uses: actions/setup-python@v7
         with:
           python-version: '3.12'
       - name: Compile Python workers

.github/workflows/frontend-mobile.yml

@@ -16,8 +16,8 @@ jobs:
       run:
         working-directory: frontend
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@v7
+      - uses: actions/setup-node@v7
         with:
           node-version: 20
           cache: npm