Update install.md
There must be a typo here - two external dependencies, not three.
@@ -29,7 +29,7 @@ import pydantic
print('compiled:', pydantic.compiled)
```
-*pydantic* has three optional dependencies:
+*pydantic* has two optional dependencies:
* If you require email validation you can add [email-validator](https://github.com/JoshData/python-email-validator)
* [dotenv file support](usage/settings.md#dotenv-env-support) with `Settings` requires
