- update to SQ 8.9.7.52159 for testing
- update to Maven 3.8.4
- use curl in AppVeyor
- close SonarOpenCommunity#2317

There is a PEG issue with the order of
```
template-parameter:
   type-parameter
   parameter-declaration
```
`type-parameter type-constraint' rule matches in case of non integral data type.

Samples:
```C++
template <typename T, size_t s = 15 > void f() {}
template <typename T, size_t s = sizeof(T)*2 > void f() {}
template <typename T, size_t s = 1>2 > void f() {}
template <values v = v::ok> void f() {}
template<class T, T::type n = 0> class X;
```