Fixed typos in the upgrading guide (#465)

Author: ssfinney

UPGRADING.md

@@ -13,7 +13,7 @@ Release notes for 5.0.0 are available [here](https://github.com/vlucas/phpdotenv
 1. The `Dotenv\Dotenv::createImmutable` and `Dotenv\Dotenv::createMutable` methods no longer call will result in `getenv` and `putenv` being called. One should instead use `Dotenv\Dotenv::createUnsafeImmutable` and `Dotenv\Dotenv::createUnsafeMutable` methods if one really needs these functions.
 2. The `Dotenv\Dotenv` constructor has been modified to expect exactly 4 parameters: a store, a parser, a loader, and a repository. This likely only affect many people, since it is more common to construct this class via the public static create methods. Those methods have not changed.
 3. Scalar typehints have been added to the public interface.
-4. The parser now returns a result type instead of raising an exception. This change is strictly internal, and most users won't notice a differnce. The responsibility for rasising an exception has simply been shifted up to the caller.
+4. The parser now returns a result type instead of raising an exception. This change is strictly internal, and most users won't notice a difference. The responsibility for raising an exception has simply been shifted up to the caller.
 5. Adapters have been refactored again, with changes to the repositories. In particular, the repository builder has been tweaked. It now expects to be explicitly told if you want to use the default adapters or not, and expects individual readers and writers to be added, one by one. Similar changes have been applied to the store factory. Moreover, the `ApacheAdapter` has been changed so that it behaves much like the other adapters. The old behaviour can be simulated by composing it with the new `ReplacingWriter` (see below). We will no longer include this adapter in our default setup, so that people can enable exactly what they need. Finally, by default, we will no longer be using the `PutenvAdapter`. It can be added, as required.
 6. Variable whitelisting has been replaced with allow listing, and the responsibility has moved from the loader to a new adapter `GuardedWriter`.
 7. The parser has been moved to its own namespace and parses entire files now. This change is expected to have little impact when upgrading. The `Lines` class has also moved to the parser namespace.