Update solargraph requirement from ~> 0.56.0 to ~> 0.57.0 (#611)

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile

@@ -11,7 +11,7 @@ group :development do
   gem "debug", "~> 1.8"
   gem "rake", "~> 13.3.0"
   gem "semver2", "~> 3.4"
-  gem "solargraph", "~> 0.56.0"
+  gem "solargraph", "~> 0.57.0"
 end
 
 group :test do