[pre-commit] Update tclint to v6.0.1

Upstream tclint updated its stable release to v6.0.1.  That version includes
the pre-commit support that was missing in v0.6.0, which required us to use an
unofficial repo [1].

Update tclint to v6.0.1.

Tested by running:
...
$ pre-commit run --all-files tclint
tclint................................................................Passed
...

[1] commit 7f6c7a5bb3 ("[pre-commit] Add tclint hook")

.pre-commit-config.yaml

@@ -88,16 +88,8 @@ repos:
       verbose: true
       always_run: true
       stages: [commit-msg]
-  - # We'd like to use the official repo, like this:
-    #   repo: https://github.com/nmoroze/tclint
-    #   rev: v0.6.0
-    # but it doesn't have a .pre-commit-hooks.yaml file.
-    # Work around this by using an unoffical repo.  The repo contains a tag
-    # v0.6.0-gdb that adds a .pre-commit-hooks.yaml file to the v0.6.0 release
-    # of the offical repo.  Since we're using an unofficial repo, use the git
-    # SHA instead of the tag.
-    repo: https://github.com/vries/tclint.git
-    rev: 2e6b4510fb3d3d6f8f2609af0f7158fabc0c96e4
+  - repo: https://github.com/nmoroze/tclint
+    rev: v0.6.1
     hooks:
     - id: tclint
       args: [--config, gdb/tclint.toml]