v0.6.9

DualNumbers v0.6.9

Diff since v0.6.8

Merged pull requests:

• enable dependabot for GitHub actions (#95) (@ranocha)
• Bump actions/cache from 1 to 3 (#96) (@dependabot[bot])
• Bump codecov/codecov-action from 1 to 3 (#97) (@dependabot[bot])
• Bump actions/checkout from 2 to 3 (#98) (@dependabot[bot])
• Fix InexactError call in convert (#99) (@jishnub)
• Add isinteger (#104) (@dlfivefifty)