Use rls-analysis 0.8

[Xanewok]

This should finalize workspace support in the RLS, modulo additional features such as tests/benches/examples 🎉

cc #132

[Xanewok]

Probably corrupted AppVeyor cache strikes again (hit only x86_64 target):

Restoring build cache
Cache 'target' - Unzipping...Error uncompressing cache item: 7z.exe process has exited with code 2. Check C:\Users\appveyor\AppData\Local\Temp\1\build-cache-logs\0e8a3ad980ec179856012b7eecf4327e99cd44cd.zip.001.log for details.
Cache 'C:\Users\appveyor\.cargo\registry' - Unzipping...Error uncompressing cache item: 7z.exe process has exited with code 2. Check C:\Users\appveyor\AppData\Local\Temp\1\build-cache-logs\bdb074cc3a948ceb4f3edc90cc30e956516562b3.zip.001.log for details.

(...)

error: this file contains an un-closed delimiter
  --> C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\git2-curl-0.7.0\src\lib.rs:38:23
   |
38 | struct CurlTransport {
   |                       ^
   |
help: did you mean to close this delimiter?
  --> C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\git2-curl-0.7.0\src\lib.rs:38:22
   |
38 | struct CurlTransport {
   |                      ^
error: aborting due to previous error
error: Could not compile `git2-curl`.
Caused by:
  process didn't exit successfully: `rustc --crate-name git2_curl C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\git2-curl-0.7.0\src\lib.rs --crate-type lib --emit=dep-info,link -C opt-level=3 -C metadata=3c0b518ae25551cb -C extra-filename=-3c0b518ae25551cb --out-dir C:\projects\rls-x6grn\target\release\deps -L dependency=C:\projects\rls-x6grn\target\release\deps --extern git2=C:\projects\rls-x6grn\target\release\deps\libgit2-2f126519536bfb1d.rlib --extern url=C:\projects\rls-x6grn\target\release\deps\liburl-1c948bcdb4477752.rlib --extern curl=C:\projects\rls-x6grn\target\release\deps\libcurl-6c3c6de68ab93a2a.rlib --extern log=C:\projects\rls-x6grn\target\release\deps\liblog-29965e230abe398c.rlib --cap-lints allow -L native=C:\projects\rls-x6grn\target\release\build\curl-sys-55cbd4f1f75a6f4d\out/lib -L C:\projects\rls-x6grn\target\release\build\libz-sys-bfeed69ef5c4027e\out/lib -L native=C:\projects\rls-x6grn\target\release\build\libgit2-sys-0fef028a2a49db3f\out/lib -L native=C:\projects\rls-x6grn\target\release\build\libssh2-sys-6849a5841cc79a8b\out/lib` (exit code: 101)
warning: build failed, waiting for other jobs to finish...
error: build failed
Command exited with code 101