Update dependency com.vladsch.flexmark:flexmark-all to v0.64.0

Author: renovate[bot]

lib/build.gradle

@@ -104,7 +104,7 @@ dependencies {
 	diktatCompileOnly "org.cqfn.diktat:diktat-rules:$VER_DIKTAT"
 
 	// used for markdown formatting
-	flexmarkCompileOnly 'com.vladsch.flexmark:flexmark-all:0.62.2'
+	flexmarkCompileOnly 'com.vladsch.flexmark:flexmark-all:0.64.0'
 
 	gsonCompileOnly 'com.google.code.gson:gson:2.10.1'