Removes el/7 and ol/7 as runners (#7650)

Removes el/7 and ol/7 as runners and update checkout action to v4

We use EL/7 and OL/7 runners to test packaging for these distributions.
However, for the past two weeks, we've encountered errors during the
checkout step in the pipelines. The error message is as follows:
```
/__e/node20/bin/node: /lib64/libm.so.6: version `GLIBC_2.27' not found (required by /__e/node20/bin/node)
/__e/node20/bin/node: /lib64/libstdc++.so.6: version `GLIBCXX_3.4.20' not found (required by /__e/node20/bin/node)
/__e/node20/bin/node: /lib64/libstdc++.so.6: version `CXXABI_1.3.9' not found (required by /__e/node20/bin/node)
/__e/node20/bin/node: /lib64/libstdc++.so.6: version `GLIBCXX_3.4.21' not found (required by /__e/node20/bin/node)
/__e/node20/bin/node: /lib64/libc.so.6: version `GLIBC_2.28' not found (required by /__e/node20/bin/node)
/__e/node20/bin/node: /lib64/libc.so.6: version `GLIBC_2.25' not found (required by /__e/node20/bin/node)
```
The GCC version within the EL/7 and OL/7 Docker images is 2.17, and we
cannot upgrade it. Therefore, we need to remove these images from the
packaging test pipelines. Consequently, we will no longer verify if the
code builds for EL/7 and OL/7.

However, we are not using these packaging images as runners within the
packaging infrastructure, so we can continue to use these images for
packaging.

Additional Info: I learned that Marlin team fully dropped the el/7
support so we will drop in further releases as well

.github/workflows/packaging-test-pipelines.yml

@@ -19,7 +19,7 @@ jobs:
       pg_versions: ${{ steps.get-postgres-versions.outputs.pg_versions }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 2
       - name: Get Postgres Versions
@@ -51,26 +51,14 @@ jobs:
           - almalinux-8
           - almalinux-9
         POSTGRES_VERSION: ${{ fromJson(needs.get_postgres_versions_from_file.outputs.pg_versions) }}
-        # Postgres removed support for CentOS 7 in PG 16. Below block is needed to
-        # keep the build for CentOS 7 working for PG 14 and PG 15.
-        # Once dependent systems drop support for Centos 7, we can remove this block.
-        include:
-          - packaging_docker_image: centos-7
-            POSTGRES_VERSION: 14
-          - packaging_docker_image: centos-7
-            POSTGRES_VERSION: 15
-          - packaging_docker_image: oraclelinux-7
-            POSTGRES_VERSION: 14
-          - packaging_docker_image: oraclelinux-7
-            POSTGRES_VERSION: 15
 
     container:
       image: citus/packaging:${{ matrix.packaging_docker_image }}-pg${{ matrix.POSTGRES_VERSION }}
       options: --user root
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set Postgres and python parameters for rpm based distros
         run: |