Bump bootstrap from 5.0.2 to 5.1.3 in /examples

Bumps [bootstrap](https://github.com/webjars/bootstrap) from 5.0.2 to 5.1.3.
- [Release notes](https://github.com/webjars/bootstrap/releases)
- [Commits](webjars/bootstrap@bootstrap-5.0.2...bootstrap-5.1.3)

---
updated-dependencies:
- dependency-name: org.webjars:bootstrap
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

examples/embedded-sass/webjars/build.gradle

@@ -2,7 +2,7 @@ apply plugin: "java"
 apply plugin: "io.freefair.sass-java"
 
 dependencies {
- implementation 'org.webjars:bootstrap:5.0.2'
+ implementation 'org.webjars:bootstrap:5.1.3'
 }
 
 compileSass {

examples/jsass/webjars/build.gradle

@@ -2,7 +2,7 @@ apply plugin: "java"
 apply plugin: "io.freefair.jsass-java"
 
 dependencies {
- implementation 'org.webjars:bootstrap:5.0.2'
+ implementation 'org.webjars:bootstrap:5.1.3'
 }
 
 compileSass {