ORC-1776: Remove MacOS 12 from GitHub Action CI and docs

This PR aims to remove `MacOS 12` from GitHub Action CI and docs.

- MacOS 12 started to release on October 25, 2021 .
- Apache ORC has 3-year support policy. We had better focus on MacOS 13+ from Apache ORC 2.1.

Pass the CIs.

No.

Closes #2026 from dongjoon-hyun/ORC-1776.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
(cherry picked from commit 6aee087)
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>
(cherry picked from commit 80b0fde)
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

.github/workflows/build_and_test.yml

@@ -48,7 +48,6 @@ jobs:
         os:
           - ubuntu-20.04
           - ubuntu-22.04
-          - macos-12
           - macos-13
           - macos-14
         java:

site/_docs/building.md

@@ -11,7 +11,7 @@ The C++ library is supported on the following operating systems:
 
 * CentOS 7
 * Debian 10 to 12
-* MacOS 12 to 14
+* MacOS 13 to 14
 * Ubuntu 20.04 to 22.04
 
 You'll want to install the usual set of developer tools, but at least: