Bump minimum Go version to 1.18, test on latest supported releases

Bump the minimum supported Go version to 1.18 in go.mod. Also make sure
CI is testing against the latest two versions supported upstream,
currently 1.21 and 1.22.

.github/workflows/test.yml

@@ -12,8 +12,8 @@ jobs:
   test:
     strategy:
       matrix:
-        # Minimum supported version (1.17) and the latest two
-        go-version: ['1.17', '1.19', '1.20']
+        # Minimum supported version (1.18) and the latest two
+        go-version: ['1.18', '1.21', '1.22']
         platform: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
 
@@ -27,7 +27,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Check formatting
-      if: matrix.go-version == '1.20' && matrix.platform == 'ubuntu-latest'
+      if: matrix.go-version == '1.22' && matrix.platform == 'ubuntu-latest'
       run: diff -u <(echo -n) <(go fmt $(go list ./...))
 
     - name: Run unit tests

go.mod

@@ -1,6 +1,6 @@
 module github.com/google/gops
 
-go 1.17
+go 1.18
 
 require (
 	github.com/shirou/gopsutil/v3 v3.24.3