Trim Galore v2.1.0-beta.7

What's Changed

• docs: GHCR tag prefix fix + README Docker example uses :beta by @FelixKrueger in #256
• docs(migration): note -a 'A{N}' poly-A divergence vs --poly_a (closes #245) by @FelixKrueger in #257
• perf(alignment): Myers' bit-parallel prefilter (#248 #4, byte-identical, co-authored) by @FelixKrueger in #258
• chore(release): v2.1.0-beta.7 + benchmark driver by @FelixKrueger in #259

Full Changelog: v2.1.0-beta.6...v2.1.0-beta.7