feat(ETHOS-43940): Remove deprecated bases

Author: Jan Michael Ong

.github/workflows/main.yml

@@ -18,16 +18,10 @@ jobs:
         # This is the default variant-less distribution (ex. 3.2.1)
         - Dockerfile: Dockerfile-ubuntu-20.04
         # Variant distributions below all have semantic versions + suffix (ex. 3.2.1-ubuntu-18.04)
-        - Dockerfile: Dockerfile-ubuntu-18.04
-          suffix: ubuntu-18.04
         - Dockerfile: Dockerfile-ubuntu-20.04
           suffix: ubuntu-20.04
         - Dockerfile: Dockerfile-ubuntu-22.04
           suffix: ubuntu-22.04
-        - Dockerfile: Dockerfile-alpine
-          suffix: alpine
-        - Dockerfile: Dockerfile-centos-7
-          suffix: centos-7
     steps:
       -
         name: Checkout

README.md

@@ -13,10 +13,6 @@ Provides base OS, security patches, and tools for quick and easy spinup.
 | ------------- | --------------------------- | ------------------ |
 | Ubuntu 20.04  |  `-VERSION#-ubuntu-20.04`   | Current            |
 | Ubuntu 22.04  |  `-VERSION#-ubuntu-22.04`   | Current            |
-| Alpine        |  `-alpine`                  | **DEPRECATED**     |
-| CentOS 7      |  `-centos-7`                | **DEPRECATED**     |
-
-`Alpine`, `CentOS 7` will be removed November 2022.
 
 ### Tools
 
@@ -38,8 +34,6 @@ On Ubuntu and CentOS-based variants, run:
 
 This file is actually a symlink to the variant-specific script contained in the `/scripts` folder
 
-NOTE: for Alpine variant, which is security-conscious, but does not have a mechanism to isolate security-specific updates, use `apk update && apk upgrade` as a generic alternative.
-
 ### Packaging
 
 A convenience script is provided for post-package installation cleanup