build(dependencies): add equatable dependency and update git sources

- Add equatable as a direct dependency in pubspec.yaml
- Update equatable version in pubspec.lock
- Set equatable dependency type to "direct main" in pubspec.lock
```

Author: fulleni

pubspec.lock

@@ -249,7 +249,7 @@ packages:
     source: git
     version: "1.0.1"
   equatable:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: equatable
       sha256: "567c64b3cb4cf82397aac55f4f0cbd3ca20d77c6c03bedbc4ceaddc08904aef7"

pubspec.yaml

@@ -40,6 +40,7 @@ dependencies:
     git:
       url: https://github.com/flutter-news-app-full-source-code/email-sendgrid.git
       ref: v1.0.1
+  equatable: ^2.0.7
   http_client:
     git:
       url: https://github.com/flutter-news-app-full-source-code/http-client.git