Installation error with R 3.6.0

Installation works correctly using R version 3.5.1 with

library(devtools)
install_github("jamesliley/subtest")

However with R version 3.6.0 I got an error:

Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.2g.Rd:36: missing link ‘pars’
fit.3g html
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:32: missing link ‘syscor’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:36: missing link ‘n_save’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:38: missing link ‘Z’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:44: missing link ‘n_save’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:46: missing link ‘pars’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:46: missing link ‘b_int’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:69: missing link ‘pars’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:49: missing link ‘3Gfit’
Rd warning: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.3g.Rd:49: missing link ‘fit_null’
fit.cond html
Error: /tmp/RtmpSmo5Gl/R.INSTALL7ee74c121c86/Subtest/man/fit.cond.Rd:58: Bad \link text

• removing ‘/home/me/R/x86_64-redhat-linux-gnu-library/3.6/Subtest’
• restoring previous ‘/home/me/R/x86_64-redhat-linux-gnu-library/3.6/Subtest’
  Error in i.p(...) :
  (converted from warning) installation of package ‘/tmp/RtmpryOObq/file7e8e64703f8f/Subtest_1.0.0.0.tar.gz’ had non-zero exit status