chore: removed deprecated license tag and bumped version

Author: manchenkoff

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "openapi3-parser"
-version = "1.2.0"
+version = "1.3.0"
 description = "OpenAPI v3 parser"
 readme = "readme.md"
 license = { file = "license.txt" }
@@ -16,7 +16,6 @@ keywords = [
   "swagger-api",
 ]
 classifiers = [
-  "License :: OSI Approved :: MIT License",
   "Operating System :: OS Independent",
   "Intended Audience :: Developers",
   "Programming Language :: Python :: 3.10",