only use upgrade on default deps

basic 🐟 completions

sort versions of packages in `rebar3 pkgs` output

escape & in paths

fix find of deps for clean all

keep plugins dir as deps dir when compiling plugins+deps

include app.src.script in app discover

fix plugin provider source name

Fix duplicate function clause in rebar_prv_install_deps:parse_dep/5

fix upgrade of newly added pkg dep from scm locked dep

Validate otp version

support atom for branch names like rebar2

In the spirit of Original Rebar's "require_min_otp_vsn", this adds
rebar_utils:check_min_otp_version/1 (taking a string containing the
minimum version) and rebar_utils:check_blacklisted_otp_versions/1
(taking a list of regular expression strings), as well as tests in
rebar_utils_SUITE. They're currently only called by the tests-
how/where to best place calls to them from non-test code needs to be
determined (at which point two corresponding rebar.config keys can be
supported). For example, the version probably shouldn't be enforced when
just running "rebar3 help".

Fix plugin upgrade when plugin mentioned only by its name

Tidy up "Linking.." messages during compile

Linking message will only be printed the first time the link or copy
actually happens.

Note:

rebar_file_utils:symlink_or_copy will now return 'exists'
instead of ok, if it did nothing because the link exists.

Nothing was checking the return value yet, so seemed reasonable.

run edoc provider in docs provider

Bumped relx to 3.4.0 and erlware_commons to 0.15.0

handle global config file that can't be read

do not install profile deps of deps

add ssl cert validation, unless OTP version is too old

Making the file up to date

Escape paths and args in shell commands

Basic escaping is done only. Fancy hex sequences are not covered, but
this should otherwise take care of the most common issues.

Fixes #497