Replaced wrong conda command against 'source'.

Signed-off-by: Daniel Scheffler <danschef@gfz-potsdam.de>
8 jobs for master in 53 minutes and 13 seconds (queued for 25 minutes and 28 seconds)
Status Job ID Name Coverage
  Test
passed #59091
test_gms_preprocessing

00:15:30

64.0%
passed #59092
test_gms_preprocessing_install

00:34:45

passed #55125
test_styles

00:00:55

passed #55123
test_urls

00:01:25

failed #55122
test_gms_preprocessing

00:14:53

64.0%
failed #55124
test_gms_preprocessing_install

00:27:50

 
  Deploy
passed #55126
pages

00:00:37

failed pages:deploy

00:00:00