Bump actions/checkout from 2 to 3

.github/workflows/cargo-audit.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout source code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Run `cargo-audit`
         uses: actions-rs/audit-check@v1

.github/workflows/check-version-bumped-aggregator.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: check-cargo-toml-version-bumped

.github/workflows/check-version-bumped-elections.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: check-cargo-toml-version-bumped

.github/workflows/check-version-bumped-finality-gadget.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: check-cargo-toml-version-bumped

.github/workflows/check-version-bumped-runtime-companion.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: check-cargo-toml-version-bumped