diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index f566fa3..167e38e 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -29,7 +29,7 @@ repos:
         args: [--profile=black]
 
   - repo: https://github.com/asottile/pyupgrade
-    rev: v3.0.0
+    rev: v3.1.0
     hooks:
       - id: pyupgrade
         args: [--py37-plus]
diff --git a/tests/conftest.py b/tests/conftest.py
index de6726f..031e637 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -15,7 +15,7 @@ def update_json_file(path: Path, d: dict):
     with open(path, "rb") as f:
         package_json = json.load(f)
     package_json.update(d)
-    with open(path, "wt") as f:
+    with open(path, "w") as f:
         json.dump(package_json, f, indent=2)