Require at least Maven 3.0 for jacoco-maven-plugin

[slachiewicz]

Fixes #194

Tests with Java 5 failed due to artifact doxia-site-renderer-1.7.4 compiled for Java 6 (from maven-reporting-impl:jar:3.0.0) - blocked by #314

[Godin]

@slachiewicz thank you for your contribution - it is good to know about connection between #194 and #314 👍 However #314 was not in our short-term plans and #194 is definitely not enough to justify #314 - Maven is not the only way of JaCoCo usage. Is there a chance that you can work on a way to resolve this without #314 ? If not, then we would prefer to close this incomplete PR.

[slachiewicz]

Unfortunately, I don't see any reasonable solution, because maven-reporting-impl is required for reporting functionality.
@khmarbaise maybe You have an idea?

[Godin]

In fact sounds strange that #194 requires #314 , because according to page https://maven.apache.org/docs/history.html Maven 3.0 was still on Java 5 😉 @slachiewicz are you sure that update of maven-reporting-impl is needed?

[slachiewicz]

Thx for the hint - simplified version added in 592d68e and sample project from our issue https://jira.apache.org/jira/browse/MDEP-82 works fine.
So no need to drop Java 5 support.

[Godin]

@marchof are you ok if in upcoming release we drop support of Maven 2.2.1 (last release in November 2009) ? If so, then I'll take care of further testing, review of documentation, etc to finalize this PR.

[marchof]

@Godin Absolutely!

[Godin]

@marchof I updated documentation and IMO this is ready to be merged.