Use go/packages instead of x/tools/loader: it allows to work
with go modules and speedups loading of packages with the help
of build cache.
A lot of linters became "fast": they are enabled by --fast now and
work in 1-2 seconds. Only unparam, interfacer and megacheck
are "slow" linters now.
Average project is analyzed 20-40% faster than before if all linters are
enabled! If we enable all linters except unparam, interfacer and
megacheck analysis is 10-20x faster!
1. Rename in a backward compatible way
2. Remove gosec default exclude list because gosec is already disabled
by default.
3. Warn about unmatched linter names in //nolint directives
4. Process linter names in //nolint directives in upper case
5. Disable gosec for golangci-lint in .golangci.yml
Although the FAQ does eventually mention that
--new-from-rev=origin/master is the right way, --help does not and
using --new in CI is a terrible pitfall.
Make --help point users to -new-from-rev=HEAD~ for CI setups.
Also use HEAD~ instead of origin/master, since HEAD~ is more
universally applicable, e.g. if golangci-lint is ran against a release
branch.
