Add a reminder to upgrade cache version when its structure is updated

tests/test_cache.py

@@ -53,6 +53,9 @@ def test_create_tables(tmp_path):
     init_cache_db(db_path)
     create_tables()
 
+    # WARNING: If you are updating this schema following a development you have made
+    # in base-worker, make sure to upgrade the arkindex_worker.cache.SQL_VERSION in
+    # the same merge request as your changes.
     expected_schema = """CREATE TABLE "classifications" ("id" TEXT NOT NULL PRIMARY KEY, "element_id" TEXT NOT NULL, "class_name" TEXT NOT NULL, "confidence" REAL NOT NULL, "state" VARCHAR(10) NOT NULL, "worker_run_id" TEXT, FOREIGN KEY ("element_id") REFERENCES "elements" ("id"))
 CREATE TABLE "dataset_elements" ("id" TEXT NOT NULL PRIMARY KEY, "element_id" TEXT NOT NULL, "dataset_id" TEXT NOT NULL, "set_name" VARCHAR(255) NOT NULL, FOREIGN KEY ("element_id") REFERENCES "elements" ("id"), FOREIGN KEY ("dataset_id") REFERENCES "datasets" ("id"))
 CREATE TABLE "datasets" ("id" TEXT NOT NULL PRIMARY KEY, "name" VARCHAR(255) NOT NULL, "state" VARCHAR(255) NOT NULL DEFAULT 'open', "sets" TEXT NOT NULL)