add missing RELEASE.md file

RELEASE.md

@@ -0,0 +1,60 @@
+Release type: patch
+
+This release adjusts the schema printer to avoid printing a schema directive
+value set to `UNSET` as `""` (empty string).
+
+For example, the following:
+
+```python
+@strawberry.input
+class FooInput:
+    a: str | None = strawberry.UNSET
+    b: str | None = strawberry.UNSET
+
+
+@strawberry.schema_directive(locations=[Location.FIELD_DEFINITION])
+class FooDirective:
+    input: FooInput
+
+
+@strawberry.type
+class Query:
+    @strawberry.field(directives=[FooDirective(input=FooInput(a="aaa"))])
+    def foo(self, info) -> str: ...
+```
+
+Would previously print as:
+
+```graphql
+directive @fooDirective(
+  input: FooInput!
+  optionalInput: FooInput
+) on FIELD_DEFINITION
+
+type Query {
+  foo: String! @fooDirective(input: { a: "aaa", b: "" })
+}
+
+input FooInput {
+  a: String
+  b: String
+}
+```
+
+Now it will be correctly printed as:
+
+```graphql
+directive @fooDirective(
+  input: FooInput!
+  optionalInput: FooInput
+) on FIELD_DEFINITION
+
+type Query {
+  foo: String! @fooDirective(input: { a: "aaa" })
+}
+
+input FooInput {
+  a: String
+  b: String
+}
+```