Adding upstream version 5.2.3+dfsg.

Signed-off-by: Daniel Baumann <daniel@debian.org>

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -0,0 +1,29 @@
+name: Feature request
+description: Suggest new or updated features to include in Bootstrap.
+title: "Suggest a new feature"
+labels: [feature]
+assignees: []
+body:
+  - type: checkboxes
+    attributes:
+      label: Prerequisites
+      description: Take a couple minutes to help our maintainers work faster.
+      options:
+        - label: I have [searched](https://github.com/twbs/bootstrap/issues?utf8=%E2%9C%93&q=is%3Aissue) for duplicate or closed feature requests
+          required: true
+        - label: I have read the [contributing guidelines](https://github.com/twbs/bootstrap/blob/main/.github/CONTRIBUTING.md)
+          required: true
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposal
+      description: Provide detailed information for what we should add, including relevant links to prior art, screenshots, or live demos whenever possible.
+    validations:
+      required: true
+  - type: textarea
+    id: motivation
+    attributes:
+      label: Motivation and context
+      description: Tell us why this change is needed or helpful, and what problems it may help solve.
+    validations:
+      required: true