Bump taiki-e/install-action from 2.68.7 to 2.68.15

Bumps [taiki-e/install-action](https://github.com/taiki-e/install-action) from 2.68.7 to 2.68.15.
- [Release notes](https://github.com/taiki-e/install-action/releases)
- [Changelog](https://github.com/taiki-e/install-action/blob/main/CHANGELOG.md)
- [Commits](taiki-e/install-action@f92912f...68675c5)

---
updated-dependencies:
- dependency-name: taiki-e/install-action
  dependency-version: 2.68.15
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -58,7 +58,7 @@ jobs:
 
       - name: Install just
         if: matrix.os != 'windows-latest'
-        uses: taiki-e/install-action@f92912fad184299a31e22ad070a5059fd07d4f59 # v2.68.7
+        uses: taiki-e/install-action@68675c5a5f1a6950c3975d33f3ae0ef155e5bf3d # v2.68.15
         with:
           tool: just
 
@@ -81,7 +81,7 @@ jobs:
 
       - name: Install taplo (for TOML formatting and linting)
         if: matrix.os != 'windows-latest'
-        uses: taiki-e/install-action@f92912fad184299a31e22ad070a5059fd07d4f59 # v2.68.7
+        uses: taiki-e/install-action@68675c5a5f1a6950c3975d33f3ae0ef155e5bf3d # v2.68.15
         with:
           tool: taplo-cli
 

.github/workflows/codecov.yml

@@ -48,7 +48,7 @@ jobs:
           fi
 
       - name: Install just
-        uses: taiki-e/install-action@f92912fad184299a31e22ad070a5059fd07d4f59 # v2.68.7
+        uses: taiki-e/install-action@68675c5a5f1a6950c3975d33f3ae0ef155e5bf3d # v2.68.15
         with:
           tool: just