CI: bump actions/checkout action to v3

Bump actions/checkout action to v3 on every workflow to mute node
deprecation warning.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
(cherry picked from commit 87c69d73bb)

.github/workflows/formal.yml

@@ -14,7 +14,7 @@ jobs:
       fail-fast: false
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0

.github/workflows/kernel.yml

@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Set lower case owner name
         id: lower_owner
@@ -83,30 +83,30 @@ jobs:
 
     steps:
       - name: Checkout master directory
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           path: openwrt
 
       - name: Checkout packages feed
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: openwrt/packages
           path: openwrt/feeds/packages
 
       - name: Checkout luci feed
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: openwrt/luci
           path: openwrt/feeds/luci
 
       - name: Checkout routing feed
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: openwrt/routing
           path: openwrt/feeds/routing
 
       - name: Checkout telephony feed
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           repository: openwrt/telephony
           path: openwrt/feeds/telephony

.github/workflows/tools.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           path: openwrt
 
@@ -102,7 +102,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           path: 'openwrt'
 
@@ -175,7 +175,7 @@ jobs:
           echo "OWNER_LC=${OWNER,,}" >> "$GITHUB_ENV"
 
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           path: 'openwrt'