chore(python): add requirements for docs build

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:007e7e46ef05e5a32e652bd0062be02f6ff050347d91e0f357b28caab0a042c4
-# created: 2024-03-15T14:27:15.879623611Z
+  digest: sha256:3741fd1f5f5150378563c76afa06bcc12777b5fe54c5ee01115218f83872134f
+# created: 2024-03-15T16:26:15.743347415Z

.kokoro/docker/docs/Dockerfile

@@ -80,4 +80,8 @@ RUN wget -O /tmp/get-pip.py 'https://bootstrap.pypa.io/get-pip.py' \
 # Test pip
 RUN python3 -m pip
 
+# Install build requirements
+COPY requirements.txt /requirements.txt
+RUN python3 -m pip install --require-hashes -r requirements.txt
+
 CMD ["python3.8"]

.kokoro/docker/docs/requirements.in

@@ -0,0 +1 @@
+nox

.kokoro/docker/docs/requirements.txt

@@ -0,0 +1,38 @@
+#
+# This file is autogenerated by pip-compile with Python 3.9
+# by the following command:
+#
+#    pip-compile --allow-unsafe --generate-hashes requirements.in
+#
+argcomplete==3.2.3 \
+    --hash=sha256:bf7900329262e481be5a15f56f19736b376df6f82ed27576fa893652c5de6c23 \
+    --hash=sha256:c12355e0494c76a2a7b73e3a59b09024ca0ba1e279fb9ed6c1b82d5b74b6a70c
+    # via nox
+colorlog==6.8.2 \
+    --hash=sha256:3e3e079a41feb5a1b64f978b5ea4f46040a94f11f0e8bbb8261e3dbbeca64d44 \
+    --hash=sha256:4dcbb62368e2800cb3c5abd348da7e53f6c362dda502ec27c560b2e58a66bd33
+    # via nox
+distlib==0.3.8 \
+    --hash=sha256:034db59a0b96f8ca18035f36290806a9a6e6bd9d1ff91e45a7f172eb17e51784 \
+    --hash=sha256:1530ea13e350031b6312d8580ddb6b27a104275a31106523b8f123787f494f64
+    # via virtualenv
+filelock==3.13.1 \
+    --hash=sha256:521f5f56c50f8426f5e03ad3b281b490a87ef15bc6c526f168290f0c7148d44e \
+    --hash=sha256:57dbda9b35157b05fb3e58ee91448612eb674172fab98ee235ccb0b5bee19a1c
+    # via virtualenv
+nox==2024.3.2 \
+    --hash=sha256:e53514173ac0b98dd47585096a55572fe504fecede58ced708979184d05440be \
+    --hash=sha256:f521ae08a15adbf5e11f16cb34e8d0e6ea521e0b92868f684e91677deb974553
+    # via -r requirements.in
+packaging==24.0 \
+    --hash=sha256:2ddfb553fdf02fb784c234c7ba6ccc288296ceabec964ad2eae3777778130bc5 \
+    --hash=sha256:eb82c5e3e56209074766e6885bb04b8c38a0c015d0a30036ebe7ece34c9989e9
+    # via nox
+platformdirs==4.2.0 \
+    --hash=sha256:0614df2a2f37e1a662acbd8e2b25b92ccf8632929bc6d43467e17fe89c75e068 \
+    --hash=sha256:ef0cc731df711022c174543cb70a9b5bd22e5a9337c8624ef2c2ceb8ddad8768
+    # via virtualenv
+virtualenv==20.25.1 \
+    --hash=sha256:961c026ac520bac5f69acb8ea063e8a4f071bcc9457b9c1f28f6b085c511583a \
+    --hash=sha256:e08e13ecdca7a0bd53798f356d5831434afa5b07b93f0abdf0797b7a06ffe197
+    # via nox