ci: move to new set-env way

[dirkdev98]

See https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-commands-for-github-actions#environment-files for more information.

Closes #386

[github-actions]

==== C8 test coverage ====
Statements: 70.27% ( 18439/26240 )
Branches : 72.09% ( 2190 /3038 )
Functions : 70.36% ( 679 /965 )
Lines : 70.27% ( 18439 /26240 )

[github-actions]

==== C8 test coverage ====
Statements: 70.27% ( 18439/26240 )
Branches : 72.09% ( 2190 /3038 )
Functions : 70.36% ( 679 /965 )
Lines : 70.27% ( 18439 /26240 )

[github-actions]

==== C8 test coverage ====
Statements: 70.27% ( 18439/26240 )
Branches : 72.09% ( 2190 /3038 )
Functions : 70.36% ( 679 /965 )
Lines : 70.27% ( 18439 /26240 )

[github-actions]

==== C8 test coverage ====
Statements: 70.27% ( 18439/26240 )
Branches : 72.09% ( 2190 /3038 )
Functions : 70.36% ( 679 /965 )
Lines : 70.27% ( 18439 /26240 )

[github-actions]

==== Benchmark result ====

Node.js version: 14
Total benchmarks: 13
          Passed: 13
          Failed: 0
-----------
lbu validator simple                    5000000  iterations      491  ns/op
yup validator simple                      20000  iterations    75582  ns/op
fastest-validator validator simple     10000000  iterations      128  ns/op
lbu validator nested                      50000  iterations    51352  ns/op
yup validator nested                       2000  iterations   544591  ns/op
fastest-validator validator nested      2000000  iterations      868  ns/op
logger - strings                         500000  iterations     2416  ns/op
logger - objects                         500000  iterations     2922  ns/op
logger - deep objects                    200000  iterations     5110  ns/op
uuid                                    2000000  iterations      619  ns/op
uuid.isValid                           10000000  iterations      145  ns/op
isNil                                 500000000  iterations        0  ns/op
isPlainObject                         100000000  iterations       19  ns/op

[github-actions]

==== C8 test coverage ====
Statements: 70.27% ( 18439/26240 )
Branches : 72.09% ( 2190 /3038 )
Functions : 70.36% ( 679 /965 )
Lines : 70.27% ( 18439 /26240 )

[github-actions]

==== Benchmark result ====

Node.js version: 15
Total benchmarks: 13
          Passed: 13
          Failed: 0
-----------
lbu validator simple                    5000000  iterations      457  ns/op
yup validator simple                      20000  iterations    59483  ns/op
fastest-validator validator simple     10000000  iterations      127  ns/op
lbu validator nested                      50000  iterations    45948  ns/op
yup validator nested                       5000  iterations   362593  ns/op
fastest-validator validator nested      2000000  iterations      767  ns/op
logger - strings                         500000  iterations     2076  ns/op
logger - objects                         500000  iterations     2442  ns/op
logger - deep objects                    500000  iterations     4284  ns/op
uuid                                    2000000  iterations      551  ns/op
uuid.isValid                           10000000  iterations      152  ns/op
isNil                                 500000000  iterations        0  ns/op
isPlainObject                         100000000  iterations       18  ns/op