Bump importlib-metadata from 3.4.0 to 3.7.3

Bumps [importlib-metadata](https://github.com/python/importlib_metadata) from 3.4.0 to 3.7.3.
- [Release notes](https://github.com/python/importlib_metadata/releases)
- [Changelog](https://github.com/python/importlib_metadata/blob/main/CHANGES.rst)
- [Commits](python/importlib_metadata@v3.4.0...v3.7.3)

Signed-off-by: dependabot[bot] <support@github.com>

Pipfile

@@ -9,9 +9,9 @@ pylint = "~=2.6.0"
 coverage = "~=5.4"
 pytest = "~=6.2.2"
 pytest-grpc = "~=0.8.0"
-mypy = "~=0.800"
+mypy = "~=0.812"
 coveralls = "~=2.2.0"
-importlib-metadata = "~=3.4.0"
+importlib-metadata = "~=3.7.3"
 pyzeebe = {editable = true, path = "."}
 sphinx = "~=3.5.1"
 sphinx-rtd-theme = "*"