docs: Link the coverage badge to the HTML report

[cicdguy]

Changes the link to the coverage badge to point to the HTML report.

[github-actions]

Unit Tests Summary

    1 files     46 suites   24s ⏱️
  498 tests   460 ✅ 38 💤 0 ❌
1 905 runs  1 863 ✅ 42 💤 0 ❌

Results for commit 6040461.

[github-actions]

Code Coverage Summary

Filename                    Stmts    Miss  Cover    Missing
------------------------  -------  ------  -------  ----------------------------
R/between-within.R             59       0  100.00%
R/component.R                  67       0  100.00%
R/cov_struct.R                 97       1  98.97%   407
R/empirical.R                   7       0  100.00%
R/fit.R                       229       3  98.69%   420, 481, 511
R/interop-car.R                72       3  95.83%   9, 48, 68
R/interop-emmeans.R            39       0  100.00%
R/interop-parsnip.R            59       1  98.31%   12
R/kenwardroger.R               92       2  97.83%   41, 63
R/mmrm-methods.R              140       0  100.00%
R/residual.R                    8       0  100.00%
R/satterthwaite.R             116      12  89.66%   238-249
R/skipping.R                    8       0  100.00%
R/testing.R                    64       4  93.75%   29, 31, 80, 82
R/tidiers.R                    72       2  97.22%   46-47
R/tmb-methods.R               281       3  98.93%   278-279, 339
R/tmb.R                       281       0  100.00%
R/utils-formula.R              27       0  100.00%
R/utils-nse.R                  16       0  100.00%
R/utils.R                     193      12  93.78%   279-289, 485, 514
R/zzz.R                        70      24  65.71%   7-22, 55-60, 90, 118, 138
src/chol_cache.h               63       0  100.00%
src/covariance.h              101       1  99.01%   177
src/derivatives.h             126       0  100.00%
src/empirical.cpp              72       0  100.00%
src/exports.cpp                47       0  100.00%
src/jacobian.cpp               47       1  97.87%   54
src/kr_comp.cpp                56       0  100.00%
src/mmrm.cpp                   76       0  100.00%
src/predict.cpp                93       0  100.00%
src/test-chol_cache.cpp        58       5  91.38%   9, 18, 26, 55, 62
src/test-covariance.cpp       123       5  95.93%   9, 29, 40, 61, 72
src/test-derivatives.cpp      108       7  93.52%   44, 53, 62, 85, 94, 106, 124
src/test-utils.cpp            195       7  96.41%   9, 16, 24, 34, 44, 57, 119
src/testthat-helpers.h         15       5  66.67%   36-37, 41, 50, 53
src/utils.h                    78       0  100.00%
TOTAL                        3255      98  96.99%

Diff against main

Filename      Stmts    Miss  Cover
----------  -------  ------  --------
TOTAL             0       0  +100.00%

Results for commit: 6040461

Minimum allowed coverage is 80%

♻️ This comment has been updated with latest results