fix spdx identifier

[thompson-tomo]

This tweaks the spdx license identifier as currently tools such as Fossa are having issues processing the declaration as it was not a valid expression. This moves the links to be in the paragraph.

For reference this how it currently appears in fossa: https://app.fossa.com/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-ruby-contrib/refs/branch/main/c1030d11596cbcd6c3a5641047abbb5ac77b54c6/browse/dependencies?title=diff-&sources%5B0%5D=managed&revisionScanId=100223864

[halostatue]

I'd be more interested in seeing the failing scan logs, because it seems to have the licence correct if for an older version of diff-lcs.

I'm disinclined to accept this PR for a number of reasons.

[thompson-tomo]

@halostatue it is not correct though, as it has treated it as 3 seperate licences whereas it should be 1 licence with 3 options seperated by the or operator. See https://app.fossa.com/projects/custom%2B162%2Fgithub.com%2Fopen-telemetry%2Fopentelemetry-ruby-contrib/refs/branch/main/c1030d11596cbcd6c3a5641047abbb5ac77b54c6/browse/dependencies?title=Net-pop&sources%5B0%5D=managed&revisionScanId=100223864 as an example of how it should be reporting.

Key thing is the identifier currently specified is not a valid expression as per https://spdx.github.io/spdx-spec/v2.3/SPDX-license-expressions/ as the linking breaks it, hence the only change is to move the links to the paragraph.

Further it is also detecting a gpl-2.0-only license which is wrong.