Update dependency rxjs to v7

Author: renovate[bot]

backend/package.json

@@ -43,7 +43,7 @@
     "readdirsync2": "1.0.2",
     "reflect-metadata": "0.1.13",
     "rimraf": "3.0.2",
-    "rxjs": "6.6.7",
+    "rxjs": "7.5.7",
     "simple-git": "2.38.0",
     "tmp": "0.2.1",
     "typeorm": "0.2.32",

backend/yarn.lock

@@ -5031,12 +5031,12 @@ rxjs@6.6.3, rxjs@^6.6.0:
   dependencies:
     tslib "^1.9.0"
 
-rxjs@6.6.7:
-  version "6.6.7"
-  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.7.tgz#90ac018acabf491bf65044235d5863c4dab804c9"
-  integrity sha512-hTdwr+7yYNIT5n4AMYp85KA6yw2Va0FLa3Rguvbpa4W3I5xynaBZo41cM3XM+4Q6fRMj3sBYIR1VAmZMXYJvRQ==
+rxjs@7.5.7:
+  version "7.5.7"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-7.5.7.tgz#2ec0d57fdc89ece220d2e702730ae8f1e49def39"
+  integrity sha512-z9MzKh/UcOqB3i20H6rtrlaE/CgjLOvheWK/9ILrbhROGTweAi1BaFsTT9FbwZi5Trr1qNRs+MXkhmR06awzQA==
   dependencies:
-    tslib "^1.9.0"
+    tslib "^2.1.0"
 
 safe-buffer@5.1.2, safe-buffer@~5.1.0, safe-buffer@~5.1.1:
   version "5.1.2"