fix: anchor tag safety (via #4789)

* v3.17.6

* release(3.17.6): rebuild dist

* add failing tests

* fix Link component

* fix OnlineValidatorBadge component

* switch from <a> to <Link> in operation components

* make Markdown inputs safe

* use Link component in Info block, for target safety

* add eslint rule for unsafe `target` usage

test/components/markdown.js

@@ -52,7 +52,7 @@ describe("Markdown component", function() {
         it("allows links", function() {
             const str = `[Link](https://example.com/)`
             const el = render(<Markdown source={str} />)
-            expect(el.html()).toEqual(`<div class="markdown"><p><a target="_blank" href="https://example.com/">Link</a></p>\n</div>`)
+            expect(el.html()).toEqual(`<div class="markdown"><p><a rel="noopener noreferrer" target="_blank" href="https://example.com/">Link</a></p>\n</div>`)
         })
     })