Speedup CI checkout (#35)

* Update build.yml to reduce fetch depth
* CI: use self-hosted runner

.github/workflows/build.yml

@@ -10,7 +10,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: [self-hosted,FlipperZeroShell]
     steps:
       - name: 'Store UID'
         id: uid
@@ -24,7 +24,11 @@ jobs:
         uses: actions/checkout@v3
         with:
           ref: ${{ github.event.pull_request.head.sha }}
-          submodules: recursive
+          fetch-depth: 1
+          
+      - name: 'Checkout submodules'
+        run:
+          git submodule update --init --recursive --depth 1 --jobs "$(getconf _NPROCESSORS_ONLN)";
 
       - name: 'Setup python'
         uses: actions/setup-python@v4