default to max supported php version

src/php.rs

@@ -106,6 +106,27 @@ impl PhpVersion {
         }
     }
 
+    pub fn from_number(major: u8, minor: u8) -> Option<Self> {
+        match (major, minor) {
+            (7, 3) => Some(PhpVersion::Php73),
+            (7, 4) => Some(PhpVersion::Php74),
+            (8, 0) => Some(PhpVersion::Php80),
+            (8, 1) => Some(PhpVersion::Php81),
+            (8, 2) => Some(PhpVersion::Php82),
+            (8, 3) => Some(PhpVersion::Php83),
+            (8, 4) => Some(PhpVersion::Php84),
+            _ => None,
+        }
+    }
+
+    pub fn max_minor(major: u8) -> u8 {
+        match major {
+            7 => 4,
+            8 => 4,
+            _ => 0,
+        }
+    }
+
     #[allow(clippy::too_many_arguments)]
     pub async fn spawn(
         &self,