* dev package bump
* test invalid header differently as node 12 no longer accepts invalid headers in response
* add node v10 in travis test list as node 12 has been released
* remove `encoding` as a dependency, throw descriptive Error if textConverted() is used without it in env
* remove rollup ext dep resolution since we don't need it
* switch to programmer error, rm unneeded test conditions, bump timeout for slow CI
* more kill `encoding` dep PR changes
keep blank "dependencies" prop in package.json so rollup's external config func doesn't seize
add ext dep checks back to the rollup config
no implicit var
clarify test comment
* [squash] alter travis cfg to test with and without `encoding`, various
fix devDeps
separate `encoding` tests to their own block
* [squash] fixing nits
* [squash] ci: full matrix of form-data versions and encoding existence
and nits
David Frank
Timothy Gu
Jared Kantrowitz
Tino Vyatkin
David Frank