Feat: version patch to 9

[jennwiederholen]

0.10.9 includes #89 , #93 , #94 , #96 , #98 , #100 , #102 , #107 , #111 , #113 , #114 , #115 , #116 , #117 , #120 , #122

[jed-wemade]

VersionMeta would be used to determine whether current gwemix version is develop or release. I think it will allow us manage version more efficiently.

• Current release version: 0.10.8-stable
• Current develop version: 0.10.9-unstable
• Next release version: 0.10.9-stable

[egonspace]

In principle, yes, but we decided to do it this way to avoid the hassle of submitting version-raising PRs twice (for both unstable and stable) with every release. We’ve documented the rule in the wiki that for temporary branches other than the dev branch, we should use the unstable version.

However, the version should not be 'officially' released until all tests have passed.