Correct the published metadata

Adds library_name to the model card, and pipeline_tag where it was missing.
Brings the config and card licenses into agreement, and repairs the variant
declarations that did not match the files actually published here.

README.md

@@ -1,5 +1,7 @@
 ---
 license: agpl-3.0
+pipeline_tag: image-segmentation
+library_name: executorch
 ---
 
 # Introduction

s/xnnpack/config.json

@@ -7,7 +7,7 @@
     "instance-segmentation"
   ],
   "backend": "xnnpack",
-  "license": "apache-2.0",
+  "license": "agpl-3.0",
   "variants": [
     {
       "file": "fast_sam_s_xnnpack_fp32.pte",
@@ -59,4 +59,4 @@
       }
     }
   ]
-}
+}

x/xnnpack/config.json

@@ -7,7 +7,7 @@
     "instance-segmentation"
   ],
   "backend": "xnnpack",
-  "license": "apache-2.0",
+  "license": "agpl-3.0",
   "variants": [
     {
       "file": "fast_sam_x_xnnpack_fp32.pte",
@@ -59,4 +59,4 @@
       }
     }
   ]
-}
+}