fix: update go version to 1.25 and use go-version-file in CI

Author: seuros

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Setup Go
       uses: actions/setup-go@v6
       with:
-        go-version: '1.25'
+        go-version-file: 'go.mod'
 
     - name: Install Mage
       run: go install github.com/magefile/mage@latest
@@ -52,7 +52,7 @@ jobs:
     - name: Setup Go
       uses: actions/setup-go@v6
       with:
-        go-version: '1.25'
+        go-version-file: 'go.mod'
 
     - name: Install Mage
       run: go install github.com/magefile/mage@latest
@@ -71,7 +71,7 @@ jobs:
     - name: Setup Go
       uses: actions/setup-go@v6
       with:
-        go-version: '1.25'
+        go-version-file: 'go.mod'
 
     - name: Install Mage
       run: go install github.com/magefile/mage@latest

go.mod

@@ -1,5 +1,5 @@
 module github.com/contriboss/rubygems-client-go
 
-go 1.25.1
+go 1.25
 
 require github.com/magefile/mage v1.15.0