chore(deps): update cimg/go docker tag to v1.25.6

Author: renovate[bot]

.circleci/config.yml

@@ -8,7 +8,7 @@ jobs:
   test_go:
     resource_class: medium
     docker:
-      - image: cimg/go:1.25.4@sha256:cf75b4671b52a5c6cd8f9c6c5dd2abe42b5f5061af89b41ae1b2ed555e7cacf9
+      - image: cimg/go:1.25.6@sha256:f6f88625e8ee23457eeb0877f5a8fea17a066ddc05958f92c093cfab791bde74
     steps:
       - checkout
       - attach_workspace:
@@ -23,7 +23,7 @@ jobs:
   build_go:
     resource_class: large
     docker:
-      - image: cimg/go:1.25.4@sha256:cf75b4671b52a5c6cd8f9c6c5dd2abe42b5f5061af89b41ae1b2ed555e7cacf9
+      - image: cimg/go:1.25.6@sha256:f6f88625e8ee23457eeb0877f5a8fea17a066ddc05958f92c093cfab791bde74
     steps:
       - checkout
       - attach_workspace:
@@ -48,7 +48,7 @@ jobs:
   publish_gh:
     resource_class: small
     docker:
-      - image: cimg/go:1.25.4@sha256:cf75b4671b52a5c6cd8f9c6c5dd2abe42b5f5061af89b41ae1b2ed555e7cacf9
+      - image: cimg/go:1.25.6@sha256:f6f88625e8ee23457eeb0877f5a8fea17a066ddc05958f92c093cfab791bde74
     steps:
       - attach_workspace:
           at: .