Update nextflow.config

Fix is a template change, see nf-core/tools#3416
If your pipeline is affected by this error I think it should be fine to manually apply this patch.

nextflow.config

@@ -340,14 +340,13 @@ env {
 }
 
 // Set bash options
-process.shell = """\
-bash
-
-set -e # Exit if a tool returns a non-zero status/exit code
-set -u # Treat unset variables and parameters as an error
-set -o pipefail # Returns the status of the last command to exit with a non-zero status or zero if all successfully execute
-set -C # No clobber - prevent output redirection from overwriting files.
-"""
+process.shell = [
+    "bash",
+    "-C",         // No clobber - prevent output redirection from overwriting files.
+    "-e",         // Exit if a tool returns a non-zero status/exit code
+    "-u",         // Treat unset variables and parameters as an error
+    "-o pipefail" // Returns the status of the last command to exit with a non-zero status or zero if all successfully execute
+]
 
 // Disable process selector warnings by default. Use debug profile to enable warnings.
 nextflow.enable.configProcessNamesValidation = false