asv benchmarks failed again

Job #83225 failed for 710b0711:

The tail of the logs reads as follows:

symengine                 0.3.0             h0cc7dce_1003    conda-forge
sympy                     1.4                      py36_0    conda-forge
tk                        8.6.9             hed695b0_1002    conda-forge
wcwidth                   0.1.7                    pypi_0    pypi
wheel                     0.33.4                   py36_0    conda-forge
xz                        5.2.4             h14c3975_1001    conda-forge
zipp                      0.5.2                    pypi_0    pypi
zlib                      1.2.11            h516909a_1005    conda-forge
fatal: ambiguous argument 'master': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

@isuruf, could you take a look?