setup: Relax Click version requirement

We were pinning the version of Click we depend on to 7.1. Pinning to a specific version of the package is not ideal, as we would have to keep updating the pinned version to avoid dependency conflicts with newer Python packages that depend on later versions of Click. We depend on some Click features that appeared in 7.1, so we do need at least this version. Later versions of the package should also work for us, so we don't need to specify the requirement so precisely. This commit relaxes the requirement to Click 7.1 or greater and less than 8. This should minimise the potential for dependency conflicts with other packages. Fixes #245

Author: rwalton-arm

news/245.bugfix

@@ -0,0 +1 @@
+Unpin Click version to minimise the potential for dependency conflicts with other packages.

setup.py

@@ -37,7 +37,7 @@
  include_package_data=True,
  install_requires=[
  "python-dotenv",
- "Click==7.1",
+ "Click>=7.1,<8",
  "pdoc3",
  "GitPython",
  "tqdm",