[pxt-cli] bump version to v8.1.6 (#6655)

[pxt-cli] bump version to v8.1.5 (#6654)

[pxt-cli] bump version to v8.1.4 (#6650)

[pxt-cli] bump version to v8.0.18 (#6634)

[pxt-cli] bump version to v8.1.3 (#6632)

[pxt-cli] bump version to v8.1.2 (#6625)

[pxt-cli] bump version to v8.0.17 (#6627)

[pxt-cli] bump version to v8.1.1 (#6618)

[pxt-cli] bump version to v8.0.16 (#6571)

[pxt-cli] bump version to v8.0.15 (#6566)