Update OpenAPI schemas for v0.13.2 of python-tools (#350)

* Update OpenAPI schemas for v0.13.0 of python-tools

* Bumped OPTIMADE spec version (1.0.1) and optimade-python-tools version (0.13.1)

* Use version number 1.0.1~develop

* Added regexp for prefix from v0.13.2 of python-tools

* Use 1.0.0~develop as the version tag

schemas/index_openapi_schema.json

@@ -2,8 +2,8 @@
   "openapi": "3.0.2",
   "info": {
     "title": "OPTIMADE API - Index meta-database",
-    "description": "The [Open Databases Integration for Materials Design (OPTIMADE) consortium](https://www.optimade.org/) aims to make materials databases interoperational by developing a common REST API.\nThis is the \"special\" index meta-database.\n\nThis specification is generated using [`optimade-python-tools`](https://github.com/Materials-Consortia/optimade-python-tools/tree/v0.12.9) v0.12.9.",
-    "version": "1.0.0"
+    "description": "The [Open Databases Integration for Materials Design (OPTIMADE) consortium](https://www.optimade.org/) aims to make materials databases interoperational by developing a common REST API.\nThis is the \"special\" index meta-database.\n\nThis specification is generated using [`optimade-python-tools`](https://github.com/Materials-Consortia/optimade-python-tools/tree/v0.13.2) v0.13.2.",
+    "version": "1.0.0~develop"
   },
   "paths": {
     "/info": {
@@ -1267,6 +1267,7 @@
           },
           "prefix": {
             "title": "Prefix",
+            "pattern": "^[a-z]([a-z]|[0-9]|_)*$",
             "type": "string",
             "description": "database-provider-specific prefix as found in section Database-Provider-Specific Namespace Prefixes."
           },