Bump actions/checkout from 2 to 3 (#144)

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -31,7 +31,7 @@ jobs:
       matrix:
         python-version: ['3.7', '3.8', '3.9', '3.10']
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: Configure SSH key for localhost

.github/workflows/pypi-release.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.repository == 'ncar-xdev/jupyter-forward'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - uses: actions/setup-python@v3

.github/workflows/upstream-dev-ci.yaml

@@ -29,7 +29,7 @@ jobs:
       matrix:
         python-version: ['3.10']
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
       - name: Configure SSH key for localhost