Update intl dependency to restore compatibility with newer Flutter localization packages

[Copilot]

After Flutter upgrades, consumers can fail dependency resolution because open_document was pinned to intl 0.18.x while newer localization stacks require 0.19.x. This PR updates package metadata to align with current Flutter dependency constraints.

• Dependency compatibility

  • Updated intl constraint in pubspec.yaml from:
    • ">=0.18.1 <0.20.0"
    • to ^0.19.0

• Package release metadata

  • Bumped package version from 1.0.7 to 1.0.8.
  • Added a 1.0.8 changelog entry documenting the intl compatibility update.

# pubspec.yamldependencies:
intl: ^0.19.0

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://storage.googleapis.com/flutter_infra_release/releases/releases_linux.json
  • Triggering command: /dependabot-proxy /dependabot-proxy (http block)
  • Triggering command: /dependabot-proxy /dependabot-proxy --bundle /run/containerd/io.containerd.runtime.v2.task/moby/31c7fca3e9fbc92f76afbdf02a1ccb9a565db2b91e4c7dc7708b79fc60891a7b --pid-file /run/containerd/io.containerd.runtime.v2.task/moby/31c7fca3e9fbc92f76afbdf02a1ccb9a565db2b91e4c7dc7708b79fc60891a7b/init.pid 31c7fca3e9fbc92f76afbdf02a1ccb9a565db2b91e4c7dc7708b79fc60891a7b (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)