Mass-migrate string formatting to f-strings

Using https://pypi.org/project/flynt. No expectation diffs. Inspired by
http://fxrev.dev/796162.

Bug: b/240137096
Change-Id: I1f0824fca1bfb6ec096b05e318625df76fa0be4d
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/127391
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Pigweed-Auto-Submit: Rob Mohr <mohrr@google.com>
Reviewed-by: Ted Pudlik <tpudlik@google.com>
diff --git a/recipe_modules/environment/api.py b/recipe_modules/environment/api.py
index 9ba78ca..468ae91 100644
--- a/recipe_modules/environment/api.py
+++ b/recipe_modules/environment/api.py
@@ -128,11 +128,11 @@
         venv_dir = env.dir.join('venv')
 
         self.m.file.ensure_directory(
-            'mkdir {}'.format(self.m.path.basename(env.dir)), env.dir,
+            f'mkdir {self.m.path.basename(env.dir)}', env.dir,
         )
 
         self.m.file.ensure_directory(
-            'mkdir {}'.format(self.m.path.basename(venv_dir)), venv_dir,
+            f'mkdir {self.m.path.basename(venv_dir)}', venv_dir,
         )
 
         cmd = [
@@ -190,8 +190,7 @@
                                 continue
 
                             self.m.file.read_text(
-                                'read {}'.format(self.m.path.basename(entry)),
-                                entry,
+                                f'read {self.m.path.basename(entry)}', entry,
                             )
 
         json_data = self.m.file.read_json(