added public to all methods

Author: sergeycherkasovv

app/src/main/java/hexlet/code/schemas/StringSchema.java

@@ -4,17 +4,17 @@
 
 public final class StringSchema extends BaseSchema<String> {
 
-    StringSchema required() {
+    public StringSchema required() {
         addValidation("required", Objects::nonNull);
         return this;
     }
 
-    StringSchema minLength(int minSize) {
+    public StringSchema minLength(int minSize) {
         addValidation("minLength", s -> s.length() >= minSize);
         return this;
     }
 
-    StringSchema contains(String contain) {
+    public StringSchema contains(String contain) {
         addValidation("contains", s -> s.contains(contain));
         return this;
     }