v0.8.1

QuanticsGrids v0.8.1

Diff since v0.8.0

Merged pull requests:

• ci: test the declared julia floor (1.8) (#40) (@shinaoka)
• Add periodic central finite differences (1st/2nd order) on a grid (#41) (@shinaoka)

Closed issues:

• CI never tests the declared julia floor (now 1.8), so it drifted from 1.6 silently (#39)