Build updates (#148)

Remove CentOS7 since it's nearing EOL and fails to build using actions/checkout@v4 and v3 will soon not be an option.

Author: hdholm

.github/workflows/build.yml

@@ -1,7 +1,13 @@
 ---
 name: build
 
-on: [push, pull_request]
+on:
+  push:
+    paths-ignore:
+      - '**.md'
+  pull_request:
+    paths-ignore:
+      - '**.md'
 
 jobs:
   linux:
@@ -35,11 +41,8 @@ jobs:
           - compiler: clang
             os: ubuntu:devel
             stable: false
-          - compiler: gcc
-            os: centos:7
-            stable: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Show OS information
         run: |
@@ -87,7 +90,7 @@ jobs:
           - gcc
           - clang
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Show OS information
         run: |