Fix IPFS cat decoding for ipfs-http-client 56 (Uint8Array)

ipfs-http-client 56 yields Uint8Array chunks, whose toString() returns
comma-separated byte values rather than text. Concatenating those turned
every document into an invalid JSON string ("123,10,32,..."), so
JSON.parse failed with "Unexpected non-whitespace character after JSON at
position 3" and no IPFS-backed record could be read.

Decode the chunks explicitly with a streaming TextDecoder, which works in
both Node and browsers. Bump version to 7.5.1.

lib/utils/ipfs.js

@@ -50,11 +50,15 @@ class IPFS {
       return fetch(`${this._config['gatewayUrl']}/${ipfsHash}`).then(r => r.text());
     } else {
       const res = this._ipfsAPI.cat(ipfsHash);
+      // ipfs-http-client >= 56 yields Uint8Array chunks. Their toString()
+      // returns comma-separated byte values instead of text, so decode the
+      // bytes explicitly (TextDecoder works in both Node and browsers).
+      const decoder = new TextDecoder();
       let str = '';
-      for await (const buffer of res) {
-        str += buffer.toString();
+      for await (const chunk of res) {
+        str += decoder.decode(chunk, { stream: true });
       }
-      return Promise.resolve(str);
+      return Promise.resolve(str + decoder.decode());
     }
   }
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kredits/contracts",
-  "version": "7.5.0",
+  "version": "7.5.1",
   "description": "Smart contracts and JavaScript API for Kredits",
   "main": "./lib/kredits.js",
   "directories": {