Bump com.icegreen:greenmail from 2.1.7 to 2.1.8

Bumps [com.icegreen:greenmail](https://github.com/greenmail-mail-test/greenmail) from 2.1.7 to 2.1.8.
- [Release notes](https://github.com/greenmail-mail-test/greenmail/releases)
- [Commits](greenmail-mail-test/greenmail@release-2.1.7...release-2.1.8)

---
updated-dependencies:
- dependency-name: com.icegreen:greenmail
  dependency-version: 2.1.8
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

pom.xml

@@ -1435,7 +1435,7 @@ under the License.
       <dependency>
         <groupId>com.icegreen</groupId>
         <artifactId>greenmail</artifactId>
-        <version>2.1.7</version>
+        <version>2.1.8</version>
         <exclusions>
           <exclusion>
             <groupId>com.sun.mail</groupId>