build(deps): bump terser from 1.1.18 to 1.1.20

Bumps [terser](https://github.com/ahorek/terser-ruby) from 1.1.18 to 1.1.20.
- [Release notes](https://github.com/ahorek/terser-ruby/releases)
- [Changelog](https://github.com/ahorek/terser-ruby/blob/master/CHANGELOG.md)
- [Commits](ahorek/terser-ruby@1.1.18...1.1.20)

---
updated-dependencies:
- dependency-name: terser
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -132,7 +132,7 @@ GEM
       ruby2_keywords
     ed25519 (1.3.0)
     erubi (1.12.0)
-    execjs (2.8.1)
+    execjs (2.9.1)
     factory_bot (6.4.2)
       activesupport (>= 5.0.0)
     factory_bot_rails (6.4.2)
@@ -352,7 +352,7 @@ GEM
     sshkit (1.21.5)
       net-scp (>= 1.1.2)
       net-ssh (>= 2.8.0)
-    terser (1.1.18)
+    terser (1.1.20)
       execjs (>= 0.3.0, < 3)
     thor (1.3.0)
     tilt (2.2.0)