Implementation-Version spans 2 lines in MANIFEST.MF in our JARs [LUCENE-7023]

The release smoke tester is angry about this.

In the core Lucene jar for 5.4.1 we have this:

```
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.8.4
Created-By: 1.7.0_55-b13 (Oracle Corporation)
Extension-Name: org.apache.lucene
Specification-Title: Lucene Search Engine: core
Specification-Version: 5.4.1
Specification-Vendor: The Apache Software Foundation
Implementation-Title: org.apache.lucene
Implementation-Version: 5.4.1 1725212 - jpountz - 2016-01-18 11:44:59
Implementation-Vendor: The Apache Software Foundation
X-Compile-Source-JDK: 1.7
X-Compile-Target-JDK: 1.7
```

But in the RC0 I'm building, I see this:

```
Ant-Version: Apache Ant 1.8.4
Created-By: 1.7.0_71-b14 (Oracle Corporation)
Extension-Name: org.apache.lucene
Specification-Title: Lucene Search Engine: queryparser
Specification-Version: 5.5.0
Specification-Vendor: The Apache Software Foundation
Implementation-Title: org.apache.lucene
Implementation-Version: 5.5.0 850c6c248373d80617e771f776041fd0d59ac31a
- mike - 2016-02-11 11:48:18
Implementation-Vendor: The Apache Software Foundation
X-Compile-Source-JDK: 1.7
X-Compile-Target-JDK: 1.7
```

The `Implementation-Version` spans two lines ... maybe this OK, maybe it's even required (is there a max line length in the MANIFEST.MF spec?) but it makes me nervous...

---
Migrated from [LUCENE-7023](https://issues.apache.org/jira/browse/LUCENE-7023) by Michael McCandless (@mikemccand), updated Sep 17 2021
Linked issues:
- #11144

Start with the generated MANIFEST.MF in the core Lucene JAR and the release smoke tester mentioned in the issue. Check the manifest specification's line-length and continuation rules, then reproduce the RC0 packaging output. Done means the Implementation-Version formatting is valid and no longer alarms the release smoke tester.

Written by the indexing model from the issue text.