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": "7.8.1",
     "simple-git": "2.38.0",
     "tmp": "0.2.1",
     "typeorm": "0.2.32",

backend/yarn.lock

@@ -5031,12 +5031,12 @@ [email protected], 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@7.8.1:
+  version "7.8.1"
+  resolved "https://registry.yarnpkg.com/rxjs/-/rxjs-7.8.1.tgz#6f6f3d99ea8044291efd92e7c7fcf562c4057543"
+  integrity sha512-AA3TVj+0A2iuIoQkWEK/tqFjBq2j+6PO6Y0zJcvzLAFhEFIO3HL0vls9hWLncZbAAbK0mar7oZ4V079I/qPMxg==
   dependencies:
-    tslib "^1.9.0"
+    tslib "^2.1.0"
 
 [email protected], safe-buffer@~5.1.0, safe-buffer@~5.1.1:
   version "5.1.2"