feat(manager/argocd): added support for argocd multisource

lib/modules/manager/argocd/__fixtures__/malformedApplications.yml

@@ -9,3 +9,15 @@ spec:
 # malformed application as the source section is missing
 apiVersion: argoproj.io/v1alpha1
 kind: Application
+---
+# malformed application as the sources array is empty
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+spec:
+  sources: []
+---
+# malformed application as the source is null
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+spec:
+  source: null

lib/modules/manager/argocd/__fixtures__/validApplication.yml

@@ -75,3 +75,39 @@ spec:
     chart: some/image3
     repoURL: somecontainer.registry.io:443/
     targetRevision: 1.0.0
+---
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+spec:
+  sources:
+    - chart: some/image3
+      repoURL: somecontainer.registry.io:443/
+      targetRevision: 1.0.0
+---
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+spec:
+  sources:
+    - ref: foo
+      repoURL: https://git.example.com/foo/bar.git
+      targetRevision: v1.2.0
+    - chart: some/image3
+      repoURL: somecontainer.registry.io:443/
+      targetRevision: 1.0.0
+
+---
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+spec:
+  sources:
+    - ref: foo
+      repoURL: https://git.example.com/foo/bar.git
+      targetRevision: v1.2.0
+      path: bar
+    - chart: traefik
+      repoURL: gs://helm-charts-internal
+      targetRevision: 0.0.2
+      helm:
+        valueFiles:
+          - $foo/values.yaml
+

lib/modules/manager/argocd/__fixtures__/validApplicationSet.yml

@@ -73,3 +73,46 @@ spec:
       destination:
         name: '{{server}}'
         namespace: podinfo
+---
+apiVersion: argoproj.io/v1alpha1
+kind: ApplicationSet
+metadata:
+  name: podinfo
+spec:
+  generators:
+  - clusters: {}
+  template:
+    metadata:
+      name: '{{name}}-podinfo'
+    spec:
+      project: default
+      sources:
+        - chart: some/image3
+          repoURL: somecontainer.registry.io:443/
+          targetRevision: 1.0.0
+      destination:
+        name: '{{server}}'
+        namespace: podinfo
+---
+apiVersion: argoproj.io/v1alpha1
+kind: ApplicationSet
+metadata:
+  name: podinfo
+spec:
+  generators:
+  - clusters: {}
+  template:
+    metadata:
+      name: '{{name}}-podinfo'
+    spec:
+      project: default
+      sources:
+        - ref: foo
+          repoURL: https://git.example.com/foo/bar.git
+          targetRevision: v1.2.0
+        - chart: some/image3
+          repoURL: somecontainer.registry.io:443/
+          targetRevision: 1.0.0
+      destination:
+        name: '{{server}}'
+        namespace: podinfo