docs: omit mention of Python 2.7 in 'CONTRIBUTING.rst'

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/repo-automation-bots/owlbot-python:latest
-  digest: sha256:58c7342b0bccf85028100adaa3d856cb4a871c22ca9c01960d996e66c40548ce
+  digest: sha256:b6c55c48761d2ee099a68c94452125cbe02ac746d0497a424dc77751f0d11278

.kokoro/samples/python3.9/common.cfg

@@ -0,0 +1,40 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Build logs will be here
+action {
+  define_artifacts {
+    regex: "**/*sponge_log.xml"
+  }
+}
+
+# Specify which tests to run
+env_vars: {
+    key: "RUN_TESTS_SESSION"
+    value: "py-3.9"
+}
+
+# Declare build specific Cloud project.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests-py39"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-bigquery-sqlalchemy/.kokoro/test-samples.sh"
+}
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+    key: "TRAMPOLINE_IMAGE"
+    value: "gcr.io/cloud-devrel-kokoro-resources/python-samples-testing-docker"
+}
+
+# Download secrets for samples
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/python-docs-samples"
+
+# Download trampoline resources.
+gfile_resources: "/bigstore/cloud-devrel-kokoro-resources/trampoline"
+
+# Use the trampoline script to run in docker.
+build_file: "python-bigquery-sqlalchemy/.kokoro/trampoline.sh"

.kokoro/samples/python3.9/continuous.cfg

@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}

.kokoro/samples/python3.9/periodic-head.cfg

@@ -0,0 +1,11 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}
+
+env_vars: {
+    key: "TRAMPOLINE_BUILD_FILE"
+    value: "github/python-pubsub/.kokoro/test-samples-against-head.sh"
+}

.kokoro/samples/python3.9/periodic.cfg

@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "False"
+}

.kokoro/samples/python3.9/presubmit.cfg

@@ -0,0 +1,6 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+env_vars: {
+    key: "INSTALL_LIBRARY_FROM_SOURCE"
+    value: "True"
+}

.pre-commit-config.yaml

@@ -16,7 +16,7 @@
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
 -   repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.0.1
     hooks:
     -   id: trailing-whitespace
     -   id: end-of-file-fixer

CONTRIBUTING.rst

@@ -69,14 +69,16 @@ We use `nox <https://nox.readthedocs.io/en/latest/>`__ to instrument our tests.
 
 - To test your changes, run unit tests with ``nox``::
 
-    $ nox -s unit-2.7
+    $ nox -s unit-3.6
+    $ nox -s unit-3.7
     $ nox -s unit-3.8
-    $ ...
+    $ nox -s unit-3.9
 
 - Args to pytest can be passed through the nox command separated by a `--`. For
   example, to run a single test::
 
-    $ nox -s unit-3.8 -- -k <name of test>
+    $ nox -s unit-3.9 -- -k <name of test>
+
 
   .. note::
 
@@ -144,17 +146,16 @@ Running System Tests
 
    # Run all system tests
    $ nox -s system-3.8
-   $ nox -s system-2.7
+   $ nox -s system-3.9
 
    # Run a single system test
-   $ nox -s system-3.8 -- -k <name of test>
+   $ nox -s system-3.9 -- -k <name of test>
 
 
   .. note::
 
-      System tests are only configured to run under Python 2.7 and
-      Python 3.8. For expediency, we do not run them in older versions
-      of Python 3.
+      System tests are only configured to run under Python 3.8 and 3.9.
+      For expediency, we do not run them in older versions of Python 3.
 
   This alone will not run the tests. You'll need to change some local
   auth settings and change some configuration in your project to
@@ -218,8 +219,8 @@ Supported versions can be found in our ``noxfile.py`` `config`_.
 .. _config: https://github.com/googleapis/python-bigquery-sqlalchemy/blob/master/noxfile.py
 
 
-We also explicitly decided to support Python 3 beginning with version
-3.6. Reasons for this include:
+We also explicitly decided to support Python 3 beginning with version 3.6.
+Reasons for this include:
 
 -  Encouraging use of newest versions of Python 3
 -  Taking the lead of `prominent`_ open-source `projects`_