chore: bump Go to 1.25.9 and align test matrix to 1.25/1.26

Raise the minimum Go toolchain to the latest 1.25 patch and standardize
the CI matrix so every repo is tested against 1.25 and 1.26.

Author: appleboy

.github/workflows/testing.yml

@@ -39,7 +39,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest]
-        go: [1.25, 1.26, stable]
+        go: [1.25, 1.26]
         include:
           - os: ubuntu-latest
             go-build: ~/.cache/go-build

go.mod

@@ -1,6 +1,6 @@
 module github.com/appleboy/CodeGPT
 
-go 1.25.0
+go 1.25.9
 
 require (
 	github.com/appleboy/com v1.2.0