Merge branch 'add-renovate-file' into 'development'

add renovate.json file

See merge request !4

renovate.json

+{
+    "assignees": [
+      "@cvernooy"
+    ],
+    "baseBranches": [
+      "development"
+    ],
+    "packageRules": [
+        {
+            "datasources": ["docker"],
+            "packageNames": ["gcr.io/spark-operator/spark-operator"],
+            "versioning": "regex:^v1beta2-(?<major>\\d+).(?<minor>\\d+).(?<patch>\\d+)(-(?<compatibility>.*))$"
+        }
+    ],
+    "regexManagers": [
+        {
+            "fileMatch": [
+                "^hardening_manifest.yaml$"
+            ],
+            "matchStrings": [
+                "org\\.opencontainers\\.image\\.version:\\s+\"(?<currentValue>.+?)\""
+            ],
+            "depNameTemplate": "gcr.io/spark-operator/spark-operator",
+            "datasourceTemplate": "docker"
+        },
+        {
+            "fileMatch": [
+                "^hardening_manifest.yaml$"
+            ],
+            "matchStrings": [
+                "tags:\\s+-\\s+\"(?<currentValue>.+?)\""
+            ],
+            "depNameTemplate": "gcr.io/spark-operator/spark-operator",
+            "datasourceTemplate": "docker"
+        }
+    ]
+}