drop support for python 3.7

[McKnight-42]

resolves #792

Description

Checklist

• [x] I have read the contributing guide and understand what's expected of me
• [x] I have signed the CLA
• [ ] I have run this code in development and it appears to resolve the stated issue
• [ ] This PR includes tests, or tests are not required/relevant for this PR
• [ ] I have opened an issue to add/update docs, or docs changes are not required/relevant for this PR
• [x] I have run changie new to create a changelog entry

[github-actions[bot]]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the dbt-spark contributing guide.

[github-actions[bot]]

The backport to 1.5.latest failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-1.5.latest 1.5.latest
# Navigate to the new working tree
cd .worktrees/backport-1.5.latest
# Create a new branch
git switch --create backport-793-to-1.5.latest
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 1ecd8e902d0451c3a0c0db8393eeeef13f933516
# Push it to GitHub
git push --set-upstream origin backport-793-to-1.5.latest
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-1.5.latest

Then, create a pull request where the base branch is 1.5.latest and the compare/head branch is backport-793-to-1.5.latest.