Add dependabot & update workflows (#344)

* Add dependabot & update workflows

* Specify python-version & use pip cache

* Add requirements.txt

* Cache PIP generally instead & remove requirements

.github/dependabot.yml

@@ -0,0 +1,8 @@
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      # Check for updates to GitHub Actions every week
+      interval: "weekly"

.github/workflows/actions.yml

@@ -9,21 +9,29 @@ jobs:
     runs-on: ubuntu-20.04
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cache/pip
+            ~/.platformio/.cache
+          key: ${{ runner.os }}-pio
 
       - name: Set up Python
-        uses: actions/setup-python@v1
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
 
-      - name: Install pio and its dependencies
+      - name: Install PlatformIO and its dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install platformio
+          pip install --upgrade platformio
 
       - name: Run builds
         run: python ./ci/build.py
 
       - name: Upload binaries
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: binaries
           path: ./build/*.bin

.github/workflows/release.yml

@@ -1,6 +1,6 @@
 name: Releases
 
-on: 
+on:
   push:
     tags:
     - '*'
@@ -12,9 +12,9 @@ jobs:
     permissions:
       contents: write
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - uses: ncipollo/release-action@v1
       with:
         artifacts: "./build/*.bin"
         draft: true
-        token: ${{ secrets.GITHUB_TOKEN }}
+        token: ${{ secrets.GITHUB_TOKEN }}