Use the new api-clients/psr7-oauth1 package (thanks to @simensen)

Author: WyriHaximus

composer.json

@@ -12,6 +12,7 @@
   "require": {
     "php": "^7.0",
     "api-clients/middleware": "dev-master",
+    "api-clients/psr7-oauth1": "dev-master",
     "guzzlehttp/psr7": "^1.3",
     "jacobkiers/oauth": "^1.0",
     "wyrihaximus/ticking-promise": "^1.6"