Fix outputs schema

[medikoo]

Fixes #506

After serverless/serverless#8319 in some schema scenarios primitives got converted to arrays, and that happened for outputs

This patch ensures it's not the case.

Additionally it fixes the issue of too restrictive outputs name schema. It followed restrictions on AWS side, while on our side there are no name restrictions

[codecov]

Codecov Report

Merging #507 into master will increase coverage by 9.56%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #507      +/-   ##
==========================================
+ Coverage   48.58%   58.14%   +9.56%     
==========================================
  Files          89       67      -22     
  Lines        2822     2143     -679     
==========================================
- Hits         1371     1246     -125     
+ Misses       1451      897     -554     

Impacted Files	Coverage Δ
lib/plugin.js	87.50% <ø> (ø)
test/index.js
src/lib/transaction.js
.../lib/eventDetection/eventTypes/customAuthorizer.js
src/lib/eventDetection/eventTypes/apiGateway.js
src/lib/eventDetection/eventTypes/sns.js
src/lib/frameworks/index.js
src/lib/spanHooks/hookHttp.js
src/lib/frameworks/wrappers/lambda-api.js
src/lib/eventDetection/eventTypes/kinesis.js
... and 13 more

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