Use Alpine Linux v3.16 for the Docker image. Alpine v3.16 uses OpenSS…

…L v1.1.1, whereas Alpine v3.17 uses OpenSSL v3.0.8. The newer OpenSSL version causes problems with our Twilio integration until we can upgrade the "requests" and "urllib3" Python packages. #1284

README.md

@@ -243,7 +243,7 @@ This application defines Docker images for production, testing, and development
 | Technology | End of Support | Notes | Affected Files in ci/ |
 |------------|----------------|-------|-----------------------|
 | Python 3.8 | 14 October 2024 | | Dockerfile, Dockerfile.local |
-| Alpine Linux 3.17 | 22 November 2024 | | Dockerfile, Dockerfile.local |
+| Alpine Linux 3.16 | 23 May 2024 | | Dockerfile, Dockerfile.local |
 | Postgres 11 | [9 November 2023](https://www.postgresql.org/support/versioning/) | | docker-compose.yml, docker-compose-local.yml, docker-compose-local-migrate.yml, docker-compose-test.yml |
 | localstack | None given.  The YAML files specifies v0.12.3.  As of March 2022, v0.14.1 is available. | As of March 2022, localstack requires Python 3.6-3.9. | docker-compose-local.yml |
 | bbyars/mountebank 2.4.0 | None given. | Newer versions are available. | docker-compose-local.yml |

ci/Dockerfile

@@ -1,6 +1,6 @@
 # Python 3.8 is supported until 14 October 2024.
-# Alpine Linux 3.17 is supported until 22 November 2024.
-FROM python:3.8-alpine3.17
+# Alpine Linux 3.16 is supported until 23 May 2024.
+FROM python:3.8-alpine3.16
 
 ARG GIT_SHA
 

ci/Dockerfile.local

@@ -1,6 +1,6 @@
 # Python 3.8 is supported until 14 October 2024.
-# Alpine Linux 3.17 is supported until 22 November 2024.
-FROM python:3.8-alpine3.17
+# Alpine Linux 3.16 is supported until 23 May 2024.
+FROM python:3.8-alpine3.16
 
 ENV PYTHONDONTWRITEBYTECODE=1 \
     # https://flask.palletsprojects.com/en/2.2.x/config/?highlight=flask_debug#DEBUG