Remove support for the 386, arm/v7, and ppc64le HW platforms

It takes too bloody long to build wheels for these platforms, and we
are not currently using them.

Author: jsf9k

.github/workflows/_repo-metadata.yml

@@ -48,16 +48,16 @@ jobs:
                   "description": "The supported platforms for the Docker image.",
                   "name": "image-platforms",
                   "value": [
-                      "linux/386",
+                      # The GitHub runners take forever when building
+                      # wheels for all these platforms, so we comment
+                      # out the less common ones: 386, arm/v6, arm/v7,
+                      # ppc64le, and s390x.
+                      # "linux/386",
                       "linux/amd64",
-                      # The GitHub runners run out of disk space when
-                      # building for all these platforms, so we
-                      # comment out a few of the less common ones:
-                      # arm/v6 and s390x.
                       # "linux/arm/v6",
-                      "linux/arm/v7",
+                      # "linux/arm/v7",
                       "linux/arm64",
-                      "linux/ppc64le",
+                      # "linux/ppc64le",
                       # The base Docker image does not support the
                       # riscv64 hardware platform.
                       # "linux/riscv64",

README.md

@@ -7,7 +7,7 @@
 
 [![Docker Pulls](https://img.shields.io/docker/pulls/cisagov/pshtt_reporter)](https://hub.docker.com/r/cisagov/pshtt_reporter)
 [![Docker Image Size (latest by date)](https://img.shields.io/docker/image-size/cisagov/pshtt_reporter)](https://hub.docker.com/r/cisagov/pshtt_reporter)
-[![Platforms](https://img.shields.io/badge/platforms-386%20%7C%20amd64%20%7C%20arm%2Fv7%20%7C%20arm64%20%7C%20ppc64le-blue)](https://hub.docker.com/r/cisagov/pshtt_reporter/tags)
+[![Platforms](https://img.shields.io/badge/platforms-amd64%20%7C%20arm64-blue)](https://hub.docker.com/r/cisagov/pshtt_reporter/tags)
 
 This is a Docker container that creates PDF reports for individual
 second-level domains using data collected via