removed mailjet secrets api key from config, revocked the key

.env.example

@@ -31,3 +31,12 @@
 # via getenv('STRIPE_SECRET_KEY'). Use a live key in production, a test key
 # (sk_test_...) everywhere else.
 # STRIPE_SECRET_KEY=
+
+# Mailjet API key/secret pair, also used as SMTP user/pass for the
+# smtp_mailjet transport (Mailjet's own convention). Kept out of config/sync
+# (mailjet.settings.yml and symfony_mailer.mailer_transport.smtp_mailjet.yml
+# both ship empty values) and injected in settings.php. mailjet.settings'
+# APItoken is NOT set here: the mailjet module generates and persists it
+# itself from this key/secret on first use.
+# MAILJET_API_KEY=
+# MAILJET_API_SECRET=

config/sync/mailjet.settings.yml

@@ -1,12 +1,12 @@
 _core:
   default_config_hash: xv32isu3I93u2lqD8FkaO6ekhZ62Ti5LvVvypKvf7_0
 langcode: en
-mailjet_username: cec52b4eb2d759f5372dfd194585c388
-mailjet_password: 07aaab76d591f8161158d0df79d280eb
+mailjet_username: ''
+mailjet_password: ''
 mailjet_mail: false
 mailjet_active: true
 mail_headers_allow_html_mailjet: true
 mailjet_title: 'Mailjet API module'
-APItoken: 2CA9212C81DDF1F9C43D0756F7F1B16ACD1B26843D05F9DB39A2A92E0876CE823DF00A0F0C1960D342DD6CE65A5E9515A7FDA867028FC144CBB90F606CA70187
+APItoken: ''
 mailjet_protocol: ssl
 mailjet_por: 465

config/sync/symfony_mailer.mailer_transport.smtp_mailjet.yml

@@ -6,8 +6,8 @@ id: smtp_mailjet
 label: 'SMTP mailjet'
 plugin: smtp
 configuration:
-  user: cec52b4eb2d759f5372dfd194585c388
-  pass: 07aaab76d591f8161158d0df79d280eb
+  user: ''
+  pass: ''
   host: in-v3.mailjet.com
   port: 587
   query: