## count-character

### Instructions
write a function that takes a string and a character as arguments and returns the number of times the character appears in the string.
- if the character is not in the string return 0
- if the string is empty return 0

### Expected Function

```go
func CountChar(str string, c rune) int {
    ...
}
```

### Usage

Here is a possible program to test your function:

```go
package main

import (   
    "fmt"
    "piscine"
)

func main() {
    fmt.Println(piscine.CountChar("Hello World", 'l'))
    fmt.Println(piscine.CountChar("5  balloons",5))
    fmt.Println(piscine.CountChar("   ", ' '))
    fmt.Println(piscine.CountChar("The 7 deadly sins", '7'))
}
```

And its output :

```console
$ go run .
3
0
1
1
```