feat: update strategy for reinstall (#2019)

* feat: Add updateStrategy option in the state file with 'reinstall'/'reinstallIfForbidden' choices to uninstall and apply the specific release(s) (if forbidden to update)

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Fix unit tests related to the new updateStrategy feature

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Fix unit tests related to the new updateStrategy feature

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Resolve linter issue due to cognitive complexity

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Updated index.md to describe the possible values of updateStrategy

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Add validation of updateStrategy parameter and unit test

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Updated unit test

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Removed 'reinstall' update strategy option to only have reinstallIfForbidden, cleanup of pre-sync changes, adapted unit tests

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Display affected releases that were reinstalled

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Make sure to add --wait when deleting a release to be reinstalled due to reinstallIfForbidden

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

* Apply suggestions from Copilot code review

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

---------

Signed-off-by: Simon Bouchard <sbouchard@rbbn.com>

pkg/app/app_diff_test.go

@@ -415,4 +415,28 @@ releases:
 			},
 		})
 	})
+
+	t.Run("show diff on changed selected release with reinstall", func(t *testing.T) {
+		check(t, testcase{
+			helmfile: `
+releases:
+- name: a
+  chart: incubator/raw
+  namespace: default
+  updateStrategy: reinstallIfForbidden
+- name: b
+  chart: incubator/raw
+  namespace: default
+`,
+			selectors: []string{"name=a"},
+			lists: map[exectest.ListKey]string{
+				{Filter: "^a$", Flags: listFlags("default", "default")}: `NAME	REVISION	UPDATED                 	STATUS  	CHART        	APP VERSION	NAMESPACE
+foo 	4       	Fri Nov  1 08:40:07 2019	DEPLOYED	raw-3.1.0	3.1.0      	default
+`,
+			},
+			diffed: []exectest.Release{
+				{Name: "a", Flags: []string{"--kube-context", "default", "--namespace", "default", "--reset-values"}},
+			},
+		})
+	})
 }