fix(datetime-widget): revert default date format to include timezone (#7165)

Author: demshy

dev-test/backends/azure/config.yml

@@ -30,6 +30,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/bitbucket/config.yml

@@ -28,6 +28,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/git-gateway/config.yml

@@ -27,6 +27,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/gitea/config.yml

@@ -28,6 +28,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/github/config.yml

@@ -28,6 +28,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/gitlab/config.yml

@@ -28,6 +28,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

dev-test/backends/proxy/config.yml

@@ -32,6 +32,7 @@ collections:
       - label: Publish Date
         name: date
         widget: datetime
+        format: 'YYYY-MM-DDTHH:mm'
       - label: Description
         name: description
         widget: text

packages/decap-cms-widget-datetime/src/DateTimeControl.js

@@ -64,7 +64,7 @@ class DateTimeControl extends React.Component {
 
   getFormat() {
     const { field } = this.props;
-    const format = field?.get('format') || 'YYYY-MM-DDTHH:mm';
+    const format = field?.get('format') || 'YYYY-MM-DDTHH:mm:ss.SSS[Z]';
     const dateFormat = field?.get('date_format');
     const timeFormat = field?.get('time_format');
     let inputFormat = 'YYYY-MM-DDTHH:mm';