doc: update some docs (sourcegraph#224)

Add docs and instructions for publishing a new version

Revert deps for compatibility with actions/checkout@v2 (sourcegraph#217)

fix docker image

Add --skip-deps flag to reduce memory usage (sourcegraph#212)

skip nil defInfo

feat: `textDocument/implementation` (sourcegraph#199)

Implements implementations.

Both local and remote are implemented.

Co-authored-by: TJ DeVries <devries.timothyj@gmail.com>
Co-authored-by: Chris <chrismwendt@gmail.com>

Release v1.6.7

Signed-off-by: Stephen Gutekanst <stephen@sourcegraph.com>

API docs: add tests & fix issue indexing illegal moby/moby Go code (s…

…ourcegraph#189)

* API docs: add test for failure to index moby/moby illegal Go code
* CHANGELOG: add v1.6.6 entry

Signed-off-by: Stephen Gutekanst <stephen@sourcegraph.com>

go mod tidy

Signed-off-by: Stephen Gutekanst <stephen@sourcegraph.com>

CHANGELOG: release v1.6.4

Signed-off-by: Stephen Gutekanst <stephen@sourcegraph.com>