Expose type checking dependencies into an extra

This will allow to add tox to mypre_primer so new versions of mypy
will be tested against it. It should also make it easier to
do type checking for plugin developers.

pyproject.toml

@@ -92,6 +92,11 @@ optional-dependencies.testing = [
   "time-machine>=2.15; implementation_name!='pypy'",
   "wheel>=0.44",
 ]
+optional-dependencies.type = [
+  "mypy==1.11.2",
+  "types-cachetools>=5.5.0.20240820",
+  "types-chardet>=5.0.4.6",
+]
 urls.Documentation = "https://tox.wiki"
 urls.Homepage = "http://tox.readthedocs.org"
 urls."Release Notes" = "https://tox.wiki/en/latest/changelog.html"

tox.toml

@@ -56,7 +56,7 @@ commands = [["pre-commit", "run", "--all-files", "--show-diff-on-failure", { rep
 
 [env.type]
 description = "run type check on code base"
-deps = ["mypy==1.11.2", "types-cachetools>=5.5.0.20240820", "types-chardet>=5.0.4.6"]
+extras = ["testing", "type"]
 commands = [["mypy", "src{/}tox"], ["mypy", "tests"]]
 
 [env.docs]