fix(ci): npm cache verify/clean --force/verify #656

Potentially fixing #656. Definitely improves the situation but it
is impossible to tell in advance if this will make all the other-
wise non-reproducible issues go away. Fingers crossed.

An attempt to fix the mysterious issue with npm ci

Based on a true story:
https://stackoverflow.com/a/15483897

CI failure logs: https://github.com/hyperledger/cactus/runs/2179881505?check_suite_focus=true#step:5:8

Logs
------

 npm ci
  shell: /usr/bin/bash -e {0}
  env:
    JAVA_HOME_8.0.275_x64: /opt/hostedtoolcache/jdk/8.0.275/x64
    JAVA_HOME: /opt/hostedtoolcache/jdk/8.0.275/x64
    JAVA_HOME_8_0_275_X64: /opt/hostedtoolcache/jdk/8.0.275/x64
npm ERR! cb() never called!

npm ERR! This is an error with npm itself. Please report this error at:
npm ERR!     <https://npm.community>

Signed-off-by: Peter Somogyvari <peter.somogyvari@accenture.com>

.github/workflows/ci.yml

@@ -61,6 +61,12 @@ jobs:
     - run: npm config delete proxy
     - run: npm config delete http-proxy
     - run: npm config delete https-proxy
+
+    # https://stackoverflow.com/a/15483897
+    - run: npm cache verify
+    - run: npm cache clean --force
+    - run: npm cache verify
+
     - run: npm ci
     - run: ./node_modules/.bin/lerna bootstrap
     - run: npm run build:dev:backend