[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

buildtest/builders/base.py

@@ -169,7 +169,7 @@ def shell_detection(self):
  self.shell = Shell(
  self.recipe.get("shell")
  or self.buildexecutor.executors[self.executor]._settings.get("shell")
- or 'bash'
+ or "bash"
  )
 
  # set shebang to value defined in Buildspec, if not defined then get one from Shell class