Made prefixes nullable to allow versions to not have a prefix

Author: Vxrpenter

src/main/kotlin/io/github/vxrpenter/updater/schema/DefaultUpdateSchema.kt

@@ -20,7 +20,7 @@ package io.github.vxrpenter.updater.schema
  * The default update schema
  */
 data class DefaultUpdateSchema(
-    override val prefixes: Collection<String>,
+    override val prefixes: Collection<String>? = null,
     override val divider: String = ".",
     override val classifiers: Collection<SchemaClassifier>
 ) : UpdateSchema

src/main/kotlin/io/github/vxrpenter/updater/schema/SchemaBuilder.kt

@@ -128,10 +128,8 @@ class SchemaBuilder {
     )
 
     fun build(): DefaultUpdateSchema {
-        requireNotNull(this.prefixes)
-        require(this.prefixes!!.isNotEmpty()) { "'prefix' cannot be empty" }
         require(!this.classifiers.isEmpty()) { "'classifiers' cannot be empty" }
 
-        return DefaultUpdateSchema(prefixes = prefixes!!, divider = divider, classifiers = classifiers.toList())
+        return DefaultUpdateSchema(prefixes = prefixes, divider = divider, classifiers = classifiers.toList())
     }
 }

src/main/kotlin/io/github/vxrpenter/updater/schema/UpdateSchema.kt

@@ -24,7 +24,7 @@ interface UpdateSchema {
     /**
      * Defines the beginning of a version, e.g. `v` or `v.`
      */
-    val prefixes: Collection<String>
+    val prefixes: Collection<String>?
     /**
      * The symbol that is used to divide the version components, e.g. `.` or `-`
      */
@@ -46,7 +46,8 @@ interface UpdateSchema {
      * @return the version value, with removed prefixes
      */
     fun removePrefix(value: String): String {
-        val maxLength = prefixes.maxBy { it.toCharArray().size }.toCharArray().size
+        if (prefixes == null) return value
+        val maxLength = prefixes!!.maxBy { it.toCharArray().size }.toCharArray().size
 
         for (prefix in prefixes) {
             if (!value.contains(prefix) || prefix.toCharArray().size > maxLength) continue