fix: hardcode spectral version in bin file

Author: wtrocki

CONTRIBUTING.md

@@ -1,5 +1,5 @@
-## Contributing to ruleset library
+# Contributing to ruleset library
 
-### Updating version of spectral
+## Updating version of spectral
 
-Spectral version we use is controled by `./spectral/spectral.version` file.
+Spectral version we use is controled by `./spectral/exec/rhoasapi` file

spectral/exec/rhoasapi

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-spectral_version=`cat "../spectral.version"`
+spectral_version=6.4.2
 
 spectral --version || npm install -g --force @stoplight/spectral-cli@$spectral_version