Release 1.5.1
This commit extends the documentation for monaco version 1.5.1 and
sets its version. Monaco 1.5.1 contains the following changes:
### List of changes
#### Bugfixes
* bb125fb fix: Paging in monaco was not working (#276)
* 7388bbd Fix absolute paths broken
* 7bd5a7f Fix template loading for absolute template reference
* affafab reset env variable at the end of e2e test (#266)
* 559b881 removes fs from config implementation (#266)
* 397a8b2 fix parameters in integration test (#266)
* 2440ee7 e2e test config restore environment (#266)
#### Misc changes
* 7e38119 Add licensecheck dependencies to go mod (#250)
* 72721cf Handle possible error when creating a new go http request
* cea13c5 Do not unmarshall json before sending it to api
* 0031be2 Upgrade to go 1.16
* 73c3751 afero as filesystem
* ace1513 Improve check-license-headers.sh script
#### Library updates
* dd0ce7d Bump github.com/google/go-cmp from 0.5.4 to 0.5.5
* aaf8c64 Bump github.com/spf13/afero from 1.5.1 to 1.6.0
### Documentation
* a789838 Added documentation about custom extensions #113 (#251)
* fc09d97 Added proxy documentation (#249)
* e486bf5 Added dashboards documentation (#247)
