Update golang version to v1.25.6 (#515)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.tool-versions

@@ -1,2 +1,2 @@
 nodejs 24.12.0
-golang 1.25.5
+golang 1.25.6