fixing faulty version check

main.nf

@@ -97,9 +97,17 @@ def helpMSG() {
     """
 }
 
-if( !nextflow.version.matches('20.+') ) {
-    ch_ver=Channel.from("This workflow requires Nextflow version 20.07 or greater -- You are running version $nextflow.version").view()
-    exit 1
+XX = "21"
+YY = "04"
+ZZ = "0"
+
+if ( nextflow.version.toString().tokenize('.')[0].toInteger() < XX.toInteger() ) {
+println "\033[0;33mporeCov requires at least Nextflow version " + XX + "." + YY + "." + ZZ + " -- You are using version $nextflow.version\u001B[0m"
+exit 1
+}
+else if ( nextflow.version.toString().tokenize('.')[1].toInteger() == XX.toInteger() && nextflow.version.toString().tokenize('.')[1].toInteger() < YY.toInteger() ) {
+println "\033[0;33mporeCov requires at least Nextflow version " + XX + "." + YY + "." + ZZ + " -- You are using version $nextflow.version\u001B[0m"
+exit 1
 }
 
 workflow { //start of the workflow