fix: add hashes to requirements.txt (googleapis#1544) (googleapis#1614)

* fix: add hashes to requirements.txt

and update Docker images so they require hashes.

* fix: add hashes to docker/owlbot/java/src

* Squashed commit of the following:

commit ab7384ea1c30df8ec2e175566ef2508e6c3a2acb
Author: Jeffrey Rennie <rennie@google.com>
Date:   Tue Aug 23 11:38:48 2022 -0700

    fix: remove pip install statements (googleapis#1546)

    because the tools are already installed in the docker image as of googleapis/testing-infra-docker#227

commit 302667c9ab7210da42cc337e8f39fe1ea99049ef
Author: WhiteSource Renovate <bot@renovateapp.com>
Date:   Tue Aug 23 19:50:28 2022 +0200

    chore(deps): update dependency setuptools to v65.2.0 (googleapis#1541)

    Co-authored-by: Anthonios Partheniou <partheniou@google.com>

commit 6e9054fd91d1b500cae58ff72ee9aeb626077756
Author: WhiteSource Renovate <bot@renovateapp.com>
Date:   Tue Aug 23 19:42:51 2022 +0200

    chore(deps): update dependency nbconvert to v7 (googleapis#1543)

    Co-authored-by: Anthonios Partheniou <partheniou@google.com>

commit d229a1258999f599a90a9b674a1c5541e00db588
Author: Alexander Fenster <fenster@google.com>
Date:   Mon Aug 22 15:04:53 2022 -0700

    fix: update google-gax and remove obsolete deps (googleapis#1545)

commit 13ce62621e70059b2f5e3a7bade735f91c53339c
Author: Jeffrey Rennie <rennie@google.com>
Date:   Mon Aug 22 11:08:21 2022 -0700

    chore: remove release config and script (googleapis#1540)

    We don't release to pypi anymore.

* chore: rollback java changes

to move forward with other languages until Java's docker image is fixed
Source-Link: googleapis/synthtool@4826337
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest@sha256:7fefeb9e517db2dd8c8202d9239ff6788d6852bc92dd3aac57a46059679ac9de

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

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest
-  digest: sha256:74ab2b3c71ef27e6d8b69b1d0a0c9d31447777b79ac3cd4be82c265b45f37e5e
-# created: 2022-08-22T22:07:00.791732705Z
+  digest: sha256:7fefeb9e517db2dd8c8202d9239ff6788d6852bc92dd3aac57a46059679ac9de
+# created: 2022-08-24T19:44:03.464675104Z