Add regexes for dockerfile b64 encode in apiext swagger

Signed-off-by: Zach Hill <zach@anchore.com>

anchore_engine/services/apiext/swagger/swagger.yaml

@@ -2466,7 +2466,8 @@ definitions:
     properties:
       dockerfile:
         type: string
-        description: Content of the dockerfile for the image, if available. Deprecated in favor of the 'source' field.
+        description: Base64 encoded content of the dockerfile for the image, if available. Deprecated in favor of the 'source' field.
+        pattern: "^[a-zA-Z0-9+/=]+$"
       digest:
         type: string
         description: "A full pullable digest reference for an image. e.g. docker.io/nginx@sha256:abc123. Deprecated in favor of the 'source' field"
@@ -2506,7 +2507,8 @@ definitions:
         description: A docker pull string (e.g. docker.io/nginx:latest, or docker.io/nginx@sha256:abd) to retrieve the image
       dockerfile:
         type: string
-        description: Content of the dockerfile used to build the image, if available.
+        description: Base64 encoded content of the dockerfile used to build the image, if available.
+        pattern: "^[a-zA-Z0-9+/=]+$"
   RegistryDigestSource:
     type: object
     description: An image reference using a digest in a registry, includes some extra tag and timestamp info in addition to the pull string to allow proper tag history reconstruction.
@@ -2527,7 +2529,8 @@ definitions:
         description: Optional override of the image creation time to support proper tag history construction in cases of out-of-order analysis compared to registry history for the tag
       dockerfile:
         type: string
-        description: Content of the dockerfile used to build the image, if available.
+        description: Base64 encoded content of the dockerfile used to build the image, if available.
+        pattern: "^[a-zA-Z0-9+/=]+$"
   AnalysisArchiveSource:
     type: object
     description: An image reference in the analysis archive for the purposes of loading analysis from the archive into th working set