Bump handlebars from 4.0.12 to 4.5.1 in /demo

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.0.12 to 4.5.1.
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/wycats/handlebars.js/blob/v4.5.1/release-notes.md)
- [Commits](handlebars-lang/handlebars.js@v4.0.12...v4.5.1)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

demo/yarn.lock

@@ -1418,7 +1418,7 @@ async@^1.5.2:
   resolved "https://registry.yarnpkg.com/async/-/async-1.5.2.tgz#ec6a61ae56480c0c3cb241c95618e20892f9672a"
   integrity sha1-7GphrlZIDAw8skHJVhjiCJL5Zyo=
 
-async@^2.1.4, async@^2.5.0:
+async@^2.1.4:
   version "2.6.1"
   resolved "https://registry.yarnpkg.com/async/-/async-2.6.1.tgz#b245a23ca71930044ec53fa46aa00a3e87c6a610"
   integrity sha512-fNEiL2+AZt6AlAw/29Cr0UDe4sRAHCpEHh54WMz+Bb7QfNcFw4h3loofyJpLeQs4Yx7yuqu/2dLgM5hKOs6HlQ==
@@ -2373,6 +2373,11 @@ commander@~2.13.0:
   resolved "https://registry.yarnpkg.com/commander/-/commander-2.13.0.tgz#6964bca67685df7c1f1430c584f07d7597885b9c"
   integrity sha512-MVuS359B+YzaWqjCL/c+22gfryv+mCBPHAv3zyVI2GN8EY6IRP8VwtasXn8jyyhvvq84R4ImN1OKRtcbIasjYA==
 
+commander@~2.20.3:
+  version "2.20.3"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-2.20.3.tgz#fd485e84c03eb4881c20722ba48035e8531aeb33"
+  integrity sha512-GpVkmM8vF2vQUkj2LvZmD35JxeJOLCwJ9cUkugyk2nuhbv3+mJvpLYYt+0+USMxE+oj+ey/lJEnhZw75x/OMcQ==
+
 common-tags@^1.4.0:
   version "1.8.0"
   resolved "https://registry.yarnpkg.com/common-tags/-/common-tags-1.8.0.tgz#8e3153e542d4a39e9b10554434afaaf98956a937"
@@ -4284,11 +4289,11 @@ handle-thing@^2.0.0:
   integrity sha512-d4sze1JNC454Wdo2fkuyzCr6aHcbL6PGGuFAz0Li/NcOm1tCHGnWDRmJP85dh9IhQErTc2svWFEX5xHIOo//kQ==
 
 handlebars@^4.0.3:
-  version "4.0.12"
-  resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.0.12.tgz#2c15c8a96d46da5e266700518ba8cb8d919d5bc5"
-  integrity sha512-RhmTekP+FZL+XNhwS1Wf+bTTZpdLougwt5pcgA1tuz6Jcx0fpH/7z0qd71RKnZHBCxIRBHfBOnio4gViPemNzA==
+  version "4.5.1"
+  resolved "https://registry.yarnpkg.com/handlebars/-/handlebars-4.5.1.tgz#8a01c382c180272260d07f2d1aa3ae745715c7ba"
+  integrity sha512-C29UoFzHe9yM61lOsIlCE5/mQVGrnIOrOq7maQl76L7tYPCgC1og0Ajt6uWnX4ZTxBPnjw+CUvawphwCfJgUnA==
   dependencies:
-    async "^2.5.0"
+    neo-async "^2.6.0"
     optimist "^0.6.1"
     source-map "^0.6.1"
   optionalDependencies:
@@ -6335,10 +6340,10 @@ negotiator@0.6.1:
   resolved "https://registry.yarnpkg.com/negotiator/-/negotiator-0.6.1.tgz#2b327184e8992101177b28563fb5e7102acd0ca9"
   integrity sha1-KzJxhOiZIQEXeyhWP7XnECrNDKk=
 
-neo-async@^2.5.0:
-  version "2.6.0"
-  resolved "https://registry.yarnpkg.com/neo-async/-/neo-async-2.6.0.tgz#b9d15e4d71c6762908654b5183ed38b753340835"
-  integrity sha512-MFh0d/Wa7vkKO3Y3LlacqAEeHK0mckVqzDieUKTT+KGxi+zIpeVsFxymkIiRpbpDziHc290Xr9A1O4Om7otoRA==
+neo-async@^2.5.0, neo-async@^2.6.0:
+  version "2.6.1"
+  resolved "https://registry.yarnpkg.com/neo-async/-/neo-async-2.6.1.tgz#ac27ada66167fa8849a6addd837f6b189ad2081c"
+  integrity sha512-iyam8fBuCUpWeKPGpaNMetEocMt364qkCsfL9JuhjXX6dRnguRVOfk2GZaDpPjcOKiiXCPINZC1GczQ7iTq3Zw==
 
 nice-try@^1.0.4:
   version "1.0.5"
@@ -9351,14 +9356,22 @@ uglify-es@^3.3.4:
     commander "~2.13.0"
     source-map "~0.6.1"
 
-uglify-js@3.4.x, uglify-js@^3.1.4:
+uglify-js@3.4.x:
   version "3.4.9"
   resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.4.9.tgz#af02f180c1207d76432e473ed24a28f4a782bae3"
   integrity sha512-8CJsbKOtEbnJsTyv6LE6m6ZKniqMiFWmm9sRbopbkGs3gMPPfd3Fh8iIA4Ykv5MgaTbqHr4BaoGLJLZNhsrW1Q==
   dependencies:
     commander "~2.17.1"
     source-map "~0.6.1"
 
+uglify-js@^3.1.4:
+  version "3.6.6"
+  resolved "https://registry.yarnpkg.com/uglify-js/-/uglify-js-3.6.6.tgz#7ec28c92c7131c6a096b69cd48722600cc534207"
+  integrity sha512-q3Zusqd028P8MdbarqL0I1snTZ7+IbIWiKUXVZyXMVdOSxOG2FFqLXyGlgYSqYu46SR7tR3Sk0xqN1VtvxGWnQ==
+  dependencies:
+    commander "~2.20.3"
+    source-map "~0.6.1"
+
 uglifyjs-webpack-plugin@^1.2.4:
   version "1.3.0"
   resolved "https://registry.yarnpkg.com/uglifyjs-webpack-plugin/-/uglifyjs-webpack-plugin-1.3.0.tgz#75f548160858163a08643e086d5fefe18a5d67de"