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 Name Job ID Coverage
  Test
passed test_gms_preprocessing #59091

00:15:30

64.0%
passed test_gms_preprocessing_install #59092

00:34:45

passed test_styles #55125

00:00:55

passed test_urls #55123

00:01:25

failed test_gms_preprocessing #55122

00:14:53

64.0%
failed test_gms_preprocessing_install #55124

00:27:50

 
  Deploy
passed pages #55126

00:00:37

failed pages:deploy

00:00:00