gobject-introspection: add v2.78.1

[valgur]

Summary

Changes to recipe: gobject-introspection/2.78.1

Motivation

To target a newer gobject-introspection version in the updated GTK (#25090) and related recipes (such as harfbuzz #25093).

Details

There is a newer v2.80 release available, but it involves a more substantial change to the Python runtime dependencies.
Limiting this one to a simple version bump.

---

• Read the contributing guidelines
• Checked that this PR is not a duplicate: list of PRs by recipe
• Tested locally with at least one configuration using a recent version of Conan

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 1 (60e7d15d92f721bf69b23771e9f046ae89b353a2):

• gobject-introspection/1.78.1:
  All packages built successfully! (All logs)

---

Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 1 (60e7d15d92f721bf69b23771e9f046ae89b353a2):

• gobject-introspection/1.78.1:
  All packages built successfully! (All logs)

[conan-center-bot]

This PR has been automatically merged due to Bump version or Bump dependencies label.
Read https://github.com/conan-io/conan-center-index/blob/master/docs/labels.md#bump-version to obtain more information.