Bump blackbox exporter to v0.19.0 (#999)

`no_follow_redirects` has been deprecated and replaced
with `follow_redirects` in backbox exporter v0.19.0

Signed-off-by: Christian Zenker <christian.zenker@aoe.com>

charts/prometheus-blackbox-exporter/Chart.yaml

@@ -1,8 +1,8 @@
 apiVersion: v1
 description: Prometheus Blackbox Exporter
 name: prometheus-blackbox-exporter
-version: 4.12.0
-appVersion: 0.18.0
+version: 4.13.0
+appVersion: 0.19.0
 home: https://github.com/prometheus/blackbox_exporter
 sources:
   - https://github.com/prometheus/blackbox_exporter

charts/prometheus-blackbox-exporter/values.yaml

@@ -56,7 +56,7 @@ strategy:
 
 image:
   repository: prom/blackbox-exporter
-  tag: v0.18.0
+  tag: v0.19.0
   pullPolicy: IfNotPresent
 
   ## Optionally specify an array of imagePullSecrets.
@@ -99,7 +99,7 @@ config:
       timeout: 5s
       http:
         valid_http_versions: ["HTTP/1.1", "HTTP/2.0"]
-        no_follow_redirects: false
+        follow_redirects: true
         preferred_ip_protocol: "ip4"
 
 # Set custom config path, other than default /config/blackbox.yaml. If let empty, path will be "/config/blackbox.yaml"