Merge #403: Small CI adjustments

dbcbcff ci: increase the number of workers (Antoine Poinsot)
4a1480d ci: don't run in VERBOSE, we don't use it (Antoine Poinsot)
28e670d ci: increase task timeout (Antoine Poinsot)

Pull request description:

  Trying to make the CI run faster, and avoid transient timeouts

ACKs for top commit:
  darosior:
    ACK dbcbcff

Tree-SHA512: f170a668ec6f57e3bcb74813f5ef47d52501fa003dfa6af8925987ffdb453717c5003ff689761a10ceb6c58d7ce38149b83522e009cd3b20c9217d75a3171972

Author: darosior

.cirrus.yml

@@ -2,10 +2,11 @@ task:
   name: 'Functional tests'
   container:
     image: rust:latest
+  timeout_in: 90m  # https://cirrus-ci.org/faq/#instance-timed-out
 
   env:
-    EXECUTOR_WORKERS: 1
-    VERBOSE: 1
+    EXECUTOR_WORKERS: 3
+    VERBOSE: 0
     LOG_LEVEL: debug
     TIMEOUT: 300
     BITCOIND_VERSION: 22.0