Add raw-String methods to builder

Author: malczuuu

src/main/java/io/github/malczuuu/problem4j/core/ProblemBuilder.java

@@ -6,6 +6,8 @@ public interface ProblemBuilder {
 
   ProblemBuilder type(URI type);
 
+  ProblemBuilder type(String type);
+
   ProblemBuilder title(String title);
 
   ProblemBuilder status(int status);
@@ -14,6 +16,8 @@ public interface ProblemBuilder {
 
   ProblemBuilder instance(URI instance);
 
+  ProblemBuilder instance(String instance);
+
   ProblemBuilder extension(String name, Object value);
 
   Problem build();

src/main/java/io/github/malczuuu/problem4j/core/ProblemBuilderImpl.java

@@ -21,6 +21,11 @@ public ProblemBuilder type(URI type) {
     return this;
   }
 
+  @Override
+  public ProblemBuilder type(String type) {
+    return type(URI.create(type));
+  }
+
   @Override
   public ProblemBuilder title(String title) {
     this.title = title;
@@ -45,6 +50,11 @@ public ProblemBuilder instance(URI instance) {
     return this;
   }
 
+  @Override
+  public ProblemBuilder instance(String instance) {
+    return instance(URI.create(instance));
+  }
+
   @Override
   public ProblemBuilder extension(String name, Object value) {
     extensions.put(name, value);