Error in README

[aselder]

It looks like there is an error in the documenation about config values.

The documentation mentions :root_source_code_paths, but it looks like the code is expecting :root_source_code_path

Steps to Reproduce

1. Copy the config block from README.md
2. Recompile the app (including Sentry)

Expected Result

Application compiles

Actual Result

❯ mix deps.compile sentry --force
==> sentry
Compiling 15 files (.ex)

== Compilation error in file lib/sentry/event.ex ==
** (ArgumentError) :root_source_code_path must be configured
    lib/sentry/config.ex:86: Sentry.Config.root_source_code_path/0
    lib/sentry/sources.ex:67: Sentry.Sources.load_files/0
    lib/sentry/event.ex:64: (module)
could not compile dependency :sentry, "mix compile" failed. Errors may have been logged above. You can recompile this dependency with "mix deps.compile sentry", update it with "mix deps.update sentry" or clean it with "mix deps.clean sentry"

[elliotblackburn]

It looks like this is the offending function:

sentry-elixir/lib/sentry/config.ex

Line 81 in b915794

def root_source_code_path do

it is called by the new root_source_code_paths function for backwards compatibility but that causes the error to be issued.