Bump chunky_png from 1.3.11 to 1.3.12 (#14545)

Bumps [chunky_png](https://github.com/wvanbergen/chunky_png) from 1.3.11 to 1.3.12.
- [Release notes](https://github.com/wvanbergen/chunky_png/releases)
- [Changelog](https://github.com/wvanbergen/chunky_png/blob/master/CHANGELOG.rdoc)
- [Commits](https://github.com/wvanbergen/chunky_png/compare/v1.3.11...v1.3.12)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -143,7 +143,7 @@ GEM
       activesupport (>= 4.0)
       elasticsearch (>= 2.0.0)
       elasticsearch-dsl
-    chunky_png (1.3.11)
+    chunky_png (1.3.12)
     cld3 (3.3.0)
       ffi (>= 1.1.0, < 1.12.0)
     climate_control (0.2.0)