py-simpleeval: updated to 0.9.12

0.9.12
KInd of hoping this is the last 0.9 release, and I find time to stablize as 1.0, and start the 2.0 work some time soon...

Changelog:

Remove Cyclic references (memory leak)
Add left & right shift operations (<< and >>)
Switch to GH actions & CodeCov.io for CI tests
Add extra contributors details
Reformat w/ Black + isort, and have linting of those in CI

(adam)