Release dance for level@5

[vweevers]

Prerelease, in topological order:

• [x] level@next (using new level-packager and leveldown)
  • [x] level-packager@5 (using new levelup and encoding-down)
  • [x] encoding-down@6 (due to abstract-leveldown@6)
    • [x] Remove _setupIteratorOptions (https://github.com/Level/encoding-down/pull/74)
    • [x] Prepare changelog and upgrade guide (https://github.com/Level/encoding-down/pull/73)
    • [x] Release (https://github.com/Level/encoding-down/issues/71)
  • [x] levelup@4 (using new level-iterator-stream and deferred-leveldown)
    • [x] level-iterator-stream@4 (due to readable-stream@3)
    • [x] deferred-leveldown@5 (due to abstract-leveldown@6)
    • [x] Remove IE10 from Airtap (due to readable-stream@3) (https://github.com/Level/levelup/pull/625)
    • [x] Release (https://github.com/Level/levelup/issues/623)
  • [x] Release (https://github.com/Level/packager/issues/78)
  • [x] leveldown@next (due to abstract-leveldown@6 + N-API rewrite)
  • [x] Release RC 5.0.0-0
  • [x] Patch prebuildify to handle custom targets while using --napi (https://github.com/mafintosh/prebuildify/pull/17)
  • [x] Patch node-gyp-build to handle --build-from-source (https://github.com/Level/leveldown/issues/566)
  • [x] Release RC 5.0.0-1
  • [x] Release (https://github.com/Level/level/issues/132)

Stable:

• [x] level@5 (using new leveldown)
  • [x] ~Add more tests to encoding-down~
  • [x] leveldown@5
  • [x] Release (https://github.com/Level/leveldown/issues/550)
  • [x] Release (https://github.com/Level/level/issues/123)

Work that can happen in parallel but is not necessarily blocking:

• [x] Reorder v6 upgrade guide (https://github.com/Level/abstract-leveldown/issues/317)
• [ ] Reach out to and/or canary test dependents
  • [ ] ssb and flume: https://github.com/ssbc/ssb-server/issues/598#issuecomment-449559560
  • [x] fastify-leveldb: https://github.com/fastify/fastify-leveldb/pull/18#issuecomment-449534322
  • [ ] PouchDB?
  • [ ] others?
• [x] Update awesome (https://github.com/Level/awesome/commit/1602c2c66df668def9bd2d59e91d7c71e4a9e3ee)

[ralphtheninja]

One approach to this could be:

• release encoding-down, levelup and level-packager as is (without the extra tests)
• release a new next version of leveldown
• release a new next version of level
• try out the next version of level in important dependents and collect feedback
• add tests to encoding-down (+ other modules?) based on feedback
• release leveldown
• release level
• party :balloon: :cake: and profit !

[vweevers]

@ralphtheninja Sounds good, I think. I need a little bit of time to wrap my head around it :)

[vweevers]

OK let's go for it. Having a next version of level will make testing much easier.

I've updated the tasks above.

[vweevers]

Phew. Done!