chore(python): fix docs build (#2086)

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <[email protected]>

Author: gcf-owl-bot[bot]

packages/gapic-generator/.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:52210e0e0559f5ea8c52be148b33504022e1faef4e95fbe4b32d68022af2fa7e
-# created: 2024-07-08T19:25:35.862283192Z
+  digest: sha256:94bb690db96e6242b2567a4860a94d48fa48696d092e51b0884a1a2c0a79a407
+# created: 2024-07-31T14:52:44.926548819Z

packages/gapic-generator/.kokoro/docker/docs/Dockerfile

@@ -72,19 +72,18 @@ RUN tar -xvf Python-3.10.14.tgz
 RUN ./Python-3.10.14/configure --enable-optimizations
 RUN make altinstall
 
-RUN python3.10 -m venv /venv
-ENV PATH /venv/bin:$PATH
+ENV PATH /usr/local/bin/python3.10:$PATH
 
 ###################### Install pip
 RUN wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
-  && python3 /tmp/get-pip.py \
+  && python3.10 /tmp/get-pip.py \
   && rm /tmp/get-pip.py
 
 # Test pip
-RUN python3 -m pip
+RUN python3.10 -m pip
 
 # Install build requirements
 COPY requirements.txt /requirements.txt
-RUN python3 -m pip install --require-hashes -r requirements.txt
+RUN python3.10 -m pip install --require-hashes -r requirements.txt
 
 CMD ["python3.10"]