Deal with variables that have the same prefix

[gcatanese]

The conversion doesn't work properly when variables have the same prefix: MY_VAR, MY_VAR_1, MY_VAR_2

Proposed Solution

Allow OpenAPI specification to use placeholders directly in the examples (i.e. {{MY_VAR}}, {{MY_VAR_1}}, {{MY_VAR_2}} instead of relying on (sub)string matching