Fix link to broken logo + shorten title to package title

[peterdesmet]

Description

• Use relative link for logo: should work on GitHub and pkgdown website
• Use git2rdata as title
• Fix typo in alt

Related Issue

Example

[codecov-io]

Codecov Report

Merging #54 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff          @@
##           master    #54   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          11     11           
  Lines         696    696           
=====================================
  Hits          696    696

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[ThierryO]

Thanks for the notification. The fix still needs an absolute URL since the README is also displayed at other locations where the relative URL won't work. Can you update the PR?

[peterdesmet]

Well, for the location you mention it seems the relative link also works though: https://cran.rstudio.com/web/packages/bioRad/readme/README.html

I've basically taken the approach from pkgdown itself: https://github.com/r-lib/pkgdown/blob/d01672efa3baa80fd7ab238b7143080b0daf49a4/README.Rmd#L15