Replace cfg = "host" with cfg = "exec" (#3404)

Become compatible with
`--incompatible_disable_starlark_host_transitions`, which will be
flipped in Bazel 7.

bazelbuild/bazel#17032

Author: fmeum

extras/bindata.bzl

@@ -76,7 +76,7 @@ bindata = rule(
         "extra_args": attr.string_list(),
         "_bindata": attr.label(
             executable = True,
-            cfg = "host",
+            cfg = "exec",
             default = "@com_github_kevinburke_go_bindata//go-bindata:go-bindata",
         ),
         "_go_context_data": attr.label(

extras/embed_data.bzl

@@ -135,7 +135,7 @@ go_embed_data = rule(
         "_embed": attr.label(
             default = "//go/tools/builders:embed",
             executable = True,
-            cfg = "host",
+            cfg = "exec",
         ),
         "_go_context_data": attr.label(
             default = "//:go_context_data",