[release] Missing checksums when files are configured

[aalmiray]

Task List

• Steps to reproduce provided
• Stacktrace (if present) provided
• Example that reproduces the problem (link to git repository is ideal)
• Full description of the issue provided (see below)

Steps to Reproduce

1. Configure a project with 1 extra file

files:
  artifacts:
    - path: pom.xml

2. Configure individual checksums and 1 additional algorithm

checksum:
  individual: true
  algorithms:
    - md5

3. Perform a release

Expected Behaviour

The following files should be uploaded

[INFO]   - uploading pom.xml
[INFO]   - uploading pom.xml.md5
[INFO]   - uploading pom.xml.sha256
[INFO]   - uploading checksums_md5.txt
[INFO]   - uploading checksums_sha256.txt

Actual Behaviour

The following files are uploaded

[INFO]   - uploading pom.xml
[INFO]   - uploading pom.xml.sha256
[INFO]   - uploading checksums_md5.txt
[INFO]   - uploading checksums_sha256.txt

Environment Information

• Operating System: N/A
• JReleaser Version: 0.5.0
• JDK Version: N/A