3.0.0b8

Merge pull request #254 from CodeHeeler/release-3.0.0b8

Bump version to beta8, add release notes

3.0.0b7

Merge pull request #249 from CodeHeeler/release-3.0.0b7

Bump version to beta7, add release notes

3.0.0b6

Merge pull request #244 from CodeHeeler/release-3.0.0b6

Bump version to beta6, add release notes

3.0.0b5

Merge pull request #236 from CodeHeeler/release-3.0.0b5

Bump version to beta5, add release notes

3.0.0b4

https://github.com/pulp/pulp_python/blob/master/docs/release-notes/3.0.z.rst