Adopt version 0.0.19 of the language server

[rcjsuen]

I released version 0.0.19 of the language server this morning.

It includes:

• folding support for comments
• fix for Multi-line LABEL directives highlight as errors #338
• support for handling SCTP ports in EXPOSE instructions per Docker CE 18.03
• optional warning/error for WORKDIR instructions that are not absolute paths (to try to enforce good practices per the official guidelines and recommendations document for Dockerfiles

As always, please use the following Dockerfile to test before and after behaviours!

# this is a
# long comment
# you can now fold this!

# try hitting F1
# and then typing >> Fold All Block Comments

# this is all gone!
# you don't need to read this
# fold and bye!
FROM node

# quoted multiline LABELs shouldn't be an error, see #338
LABEL "a"="b" \
    "c"="d" \
    "e"="f"

# quoted multiline ENVs shouldn't be an error, see #338
ENV "a"="b" \
    "c"="d" \
    "e"="f"

# EXPOSE should be capable of handling SCTP, new in Docker CE 18.03
EXPOSE 8080/sctp

# WORKDIR instructions that are not variables or are not absolute paths
# will now be a warning, toggle the setting below to change this
# docker.languageserver.diagnostics.instructionWorkdirRelative = "ignore" / "warning" / "error"
# defaults to "warning"
WORKDIR abc
WORKDIR $abc
WORKDIR /abc
WORKDIR C:\\abc

[StephenWeatherford]

Thanks, Remy!

[rcjsuen]

Thank you for reviewing this, Stephen!