github: Remove Windows from the test matrix

The current tests passes, but this tool is currently meant for *nix systems.

Author: bep

.github/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       matrix:
         go-version: [1.18.x, 1.19.x]
-        os: [ubuntu-latest, windows-latest]
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2

go.mod

@@ -1,3 +1,3 @@
 module github.com/bep/firstupdotenv
 
-go 1.17
+go 1.18