docs: minimum required go version is 1.18
Description
Mention the correct minimum Go version in README and CONTRIBUTING.
Related Issues
Resolves #1159 (closed)
How has this been tested?
Doc changes - tested by visual inspection.
Screenshots (if appropriate):
Types of changes
-
Bug fix (non-breaking change which fixes an issue) -
New feature (non-breaking change which adds functionality) -
Breaking change (fix or feature that would cause existing functionality to change) -
Documentation -
Chore (Related to CI or Packaging to platforms)