Fix PyO3 version to 0.26.0 on test

Author: termoshtt

Cargo.toml

@@ -16,10 +16,6 @@ serde = "1.0.228"
 
 [dev-dependencies]
 maplit = "1.0.2"
-pyo3 = { version = ">=0.26.0", features = ["auto-initialize"] }
+pyo3 = { version = "0.26.0", features = ["auto-initialize"] }
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.145"
-
-[features]
-default = []
-abi3-py38 = ["pyo3/abi3-py38"]