Use buildozer to remove deprecated automanaged tags

vendor/github.com/stretchr/testify/assert/BUILD

@@ -18,7 +18,6 @@ go_library(
         "forward_assertions.go",
         "http_assertions.go",
     ],
-    tags = ["automanaged"],
     deps = [
         "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
         "//vendor/github.com/pmezard/go-difflib/difflib:go_default_library",

vendor/github.com/stretchr/testify/mock/BUILD

@@ -13,7 +13,6 @@ go_library(
         "doc.go",
         "mock.go",
     ],
-    tags = ["automanaged"],
     deps = [
         "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
         "//vendor/github.com/pmezard/go-difflib/difflib:go_default_library",

vendor/github.com/stretchr/testify/require/BUILD

@@ -16,7 +16,6 @@ go_library(
         "require_forward.go",
         "requirements.go",
     ],
-    tags = ["automanaged"],
     deps = ["//vendor/github.com/stretchr/testify/assert:go_default_library"],
 )