build: Update dependency go to v1.25.12

Signed-off-by: go-git-renovate[bot] <245267575+go-git-renovate[bot]@users.noreply.github.com>

Author: go-git-renovate[bot]

go.mod

@@ -2,7 +2,7 @@ module github.com/go-git/cli
 
 go 1.25.0
 
-toolchain go1.25.10
+toolchain go1.25.12
 
 require (
 	github.com/go-git/go-billy/v6 v6.0.0-alpha.2