chore(deps): update actions/setup-python action to v3 (#71)

Source-Link: googleapis/synthtool@571ee2c
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:660abdf857d3ab9aabcd967c163c70e657fcc5653595c709263af5f3fa23ef67

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -13,5 +13,4 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:ed1f9983d5a935a89fe8085e8bb97d94e41015252c5b6c9771257cf8624367e6
- 
+  digest: sha256:660abdf857d3ab9aabcd967c163c70e657fcc5653595c709263af5f3fa23ef67

.github/workflows/docs.yml

@@ -10,7 +10,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: "3.10"
     - name: Install nox
@@ -26,7 +26,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: "3.10"
     - name: Install nox

.github/workflows/lint.yml

@@ -10,7 +10,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: "3.10"
     - name: Install nox

.github/workflows/unittest.yml

@@ -13,7 +13,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: ${{ matrix.python }}
     - name: Install nox
@@ -39,7 +39,7 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v2
     - name: Setup Python
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v3
       with:
         python-version: "3.10"
     - name: Install coverage