Fix missing vendor packages

The switch to urfave/cli had a use of a /v2 API, which
go modules handles correctly but vndr ignores. Downgrade
urfave/cli for now until the switch to go modules. Add
missing dependencies, which vndr now sees.
Note that CI was not catching this issue, it seems that
some part of the build process was pulling in dependencies
even if they weren't in vendor, causing the build to work.
However the vendor check was not seeing it. The ARM build
didn't pull in other dependencies into the gopath, causing
those builds to break.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

vendor/github.com/urfave/cli/flag_int64_slice.go

@@ -1,141 +0,0 @@
-package cli
-
-import (
-	"flag"
-	"fmt"
-	"strconv"
-	"strings"
-)
-
-// Int64Slice is an opaque type for []int to satisfy flag.Value and flag.Getter
-type Int64Slice []int64
-
-// Set parses the value into an integer and appends it to the list of values
-func (f *Int64Slice) Set(value string) error {
-	tmp, err := strconv.ParseInt(value, 10, 64)
-	if err != nil {
-		return err
-	}
-	*f = append(*f, tmp)
-	return nil
-}
-
-// String returns a readable representation of this value (for usage defaults)
-func (f *Int64Slice) String() string {
-	return fmt.Sprintf("%#v", *f)
-}
-
-// Value returns the slice of ints set by this flag
-func (f *Int64Slice) Value() []int64 {
-	return *f
-}
-
-// Get returns the slice of ints set by this flag
-func (f *Int64Slice) Get() interface{} {
-	return *f
-}
-
-// Int64SliceFlag is a flag with type *Int64Slice
-type Int64SliceFlag struct {
-	Name     string
-	Usage    string
-	EnvVar   string
-	FilePath string
-	Required bool
-	Hidden   bool
-	Value    *Int64Slice
-}
-
-// String returns a readable representation of this value
-// (for usage defaults)
-func (f Int64SliceFlag) String() string {
-	return FlagStringer(f)
-}
-
-// GetName returns the name of the flag
-func (f Int64SliceFlag) GetName() string {
-	return f.Name
-}
-
-// IsRequired returns whether or not the flag is required
-func (f Int64SliceFlag) IsRequired() bool {
-	return f.Required
-}
-
-// TakesValue returns true of the flag takes a value, otherwise false
-func (f Int64SliceFlag) TakesValue() bool {
-	return true
-}
-
-// GetUsage returns the usage string for the flag
-func (f Int64SliceFlag) GetUsage() string {
-	return f.Usage
-}
-
-// GetValue returns the flags value as string representation and an empty
-// string if the flag takes no value at all.
-func (f Int64SliceFlag) GetValue() string {
-	if f.Value != nil {
-		return f.Value.String()
-	}
-	return ""
-}
-
-// Apply populates the flag given the flag set and environment
-// Ignores errors
-func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
-	_ = f.ApplyWithError(set)
-}
-
-// ApplyWithError populates the flag given the flag set and environment
-func (f Int64SliceFlag) ApplyWithError(set *flag.FlagSet) error {
-	if envVal, ok := flagFromFileEnv(f.FilePath, f.EnvVar); ok {
-		newVal := &Int64Slice{}
-		for _, s := range strings.Split(envVal, ",") {
-			s = strings.TrimSpace(s)
-			if err := newVal.Set(s); err != nil {
-				return fmt.Errorf("could not parse %s as int64 slice value for flag %s: %s", envVal, f.Name, err)
-			}
-		}
-		if f.Value == nil {
-			f.Value = newVal
-		} else {
-			*f.Value = *newVal
-		}
-	}
-
-	eachName(f.Name, func(name string) {
-		if f.Value == nil {
-			f.Value = &Int64Slice{}
-		}
-		set.Var(f.Value, name, f.Usage)
-	})
-	return nil
-}
-
-// Int64Slice looks up the value of a local Int64SliceFlag, returns
-// nil if not found
-func (c *Context) Int64Slice(name string) []int64 {
-	return lookupInt64Slice(name, c.flagSet)
-}
-
-// GlobalInt64Slice looks up the value of a global Int64SliceFlag, returns
-// nil if not found
-func (c *Context) GlobalInt64Slice(name string) []int64 {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupInt64Slice(name, fs)
-	}
-	return nil
-}
-
-func lookupInt64Slice(name string, set *flag.FlagSet) []int64 {
-	f := set.Lookup(name)
-	if f != nil {
-		parsed, err := (f.Value.(*Int64Slice)).Value(), error(nil)
-		if err != nil {
-			return nil
-		}
-		return parsed
-	}
-	return nil
-}