Use swag.File instead of runtime.File

While runtime.File will be defined as an alias, that won't be seen in
the run-time, so reflection need to use swag.File instead.

#143

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

Author: kzys

go.mod

@@ -3,15 +3,13 @@ module github.com/go-openapi/validate
 go 1.14
 
 require (
-	github.com/go-openapi/analysis v0.20.0
+	github.com/go-openapi/analysis v0.21.1
 	github.com/go-openapi/errors v0.19.9
 	github.com/go-openapi/jsonpointer v0.19.5
-	github.com/go-openapi/loads v0.20.2
-	github.com/go-openapi/runtime v0.19.24
-	github.com/go-openapi/spec v0.20.3
-	github.com/go-openapi/strfmt v0.20.2
-	github.com/go-openapi/swag v0.19.14
+	github.com/go-openapi/loads v0.20.3
+	github.com/go-openapi/spec v0.20.4
+	github.com/go-openapi/strfmt v0.21.1
+	github.com/go-openapi/swag v0.21.1
 	github.com/stretchr/testify v1.7.0
 	gopkg.in/yaml.v2 v2.4.0
-	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )