Bump jnr-posix from 3.1.11 to 3.1.15 (#12610)

Bumps [jnr-posix](https://github.com/jnr/jnr-posix) from 3.1.11 to 3.1.15.
- [Release notes](https://github.com/jnr/jnr-posix/releases)
- [Commits](jnr/jnr-posix@jnr-posix-3.1.11...jnr-posix-3.1.15)

---
updated-dependencies:
- dependency-name: com.github.jnr:jnr-posix
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

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

Author: dependabot[bot]

grails-shell/build.gradle

@@ -27,7 +27,7 @@ dependencies {
     }
 
     testCompile "net.sf.expectit:expectit-core:0.9.0"
-    testCompile "com.github.jnr:jnr-posix:3.1.11"
+    testCompile "com.github.jnr:jnr-posix:3.1.15"
 
     runtime "org.slf4j:slf4j-simple:$slf4jVersion"
     runtime "org.codehaus.plexus:plexus-component-api:1.0-alpha-33"