Explicitly declare allowPrivilegeEscalation to false

Although containers that do not run as privileged already have this set to false by kubernetes
Kubespace [asks us](https://hub.armo.cloud/docs/c-0016) to explicitly declare it to false where not needed.

Signed-off-by: Arthur Silva Sens <arthursens2005@gmail.com>

manifests/blackboxExporter-deployment.yaml

@@ -42,6 +42,7 @@ spec:
             cpu: 10m
             memory: 20Mi
         securityContext:
+          allowPrivilegeEscalation: false
           runAsNonRoot: true
           runAsUser: 65534
         volumeMounts:
@@ -61,6 +62,7 @@ spec:
             cpu: 10m
             memory: 20Mi
         securityContext:
+          allowPrivilegeEscalation: false
           runAsNonRoot: true
           runAsUser: 65534
         terminationMessagePath: /dev/termination-log
@@ -87,6 +89,7 @@ spec:
             cpu: 10m
             memory: 20Mi
         securityContext:
+          allowPrivilegeEscalation: false
           runAsGroup: 65532
           runAsNonRoot: true
           runAsUser: 65532