Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

vendor/mvdan.cc/xurls/v2/README.md

@@ -0,0 +1,37 @@
+# xurls
+
+[![Go Reference](https://pkg.go.dev/badge/mvdan.cc/xurls/v2.svg)](https://pkg.go.dev/mvdan.cc/xurls/v2)
+
+Extract urls from text using regular expressions. Requires Go 1.15 or later.
+
+```go
+import "mvdan.cc/xurls/v2"
+
+func main() {
+	rxRelaxed := xurls.Relaxed()
+	rxRelaxed.FindString("Do gophers live in golang.org?")  // "golang.org"
+	rxRelaxed.FindString("This string does not have a URL") // ""
+
+	rxStrict := xurls.Strict()
+	rxStrict.FindAllString("must have scheme: http://foo.com/.", -1) // []string{"http://foo.com/"}
+	rxStrict.FindAllString("no scheme, no match: foo.com", -1)       // []string{}
+}
+```
+
+Since API is centered around [regexp.Regexp](https://golang.org/pkg/regexp/#Regexp),
+many other methods are available, such as finding the [byte indexes](https://golang.org/pkg/regexp/#Regexp.FindAllIndex)
+for all matches.
+
+Note that calling the exposed functions means compiling a regular expression, so
+repeated calls should be avoided.
+
+#### cmd/xurls
+
+To install the tool globally:
+
+	cd $(mktemp -d); go mod init tmp; GO111MODULE=on go get mvdan.cc/xurls/v2/cmd/xurls
+
+```shell
+$ echo "Do gophers live in http://golang.org?" | xurls
+http://golang.org
+```