chore(deps): bump chroma to v2 #735

Bump `alecthomas/chroma` to `v2`:
https://github.com/cheat/cheat/issues/735

vendor/github.com/alecthomas/chroma/v2/.gitignore

@@ -0,0 +1,25 @@
+# Binaries for programs and plugins
+.git
+.idea
+.vscode
+.hermit
+*.exe
+*.dll
+*.so
+*.dylib
+/cmd/chroma/chroma
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
+.glide/
+
+_models/
+
+_examples/
+*.min.*
+build/