Update README

ICSharpCode.Decompiler.Console/README.md

@@ -25,6 +25,10 @@ Options:
   -d|--debuginfo                       Generate PDB.
   -l|--list <entity-type(s)>           Lists all entities of the specified type(s). Valid types: c(lass), i(interface), s(truct), d(elegate), e(num)
   -v|--version                         Show version of ICSharpCode.Decompiler used.
+  -lv|--languageversion <version>      C# Language version: CSharp1, CSharp2, CSharp3, CSharp4, CSharp5, CSharp6, CSharp7_0, CSharp7_1, CSharp7_2, CSharp7_3, CSharp8_0 or Latest
+  -r|--referencepath <path>            Path to a directory containing dependencies of the assembly that is being decompiled.
+  --no-dead-code                       Remove dead code.
+  --no-dead-stores                     Remove dead stores.
 
 Remarks:
   -o is valid with every option and required when using -p.