curl: bump to 7.60.0

Refresh patches; remove 320-mbedtls_dont_use_deprecated_sha256_function
patch as upstream fixed

For changes in version 2.60 see https://curl.haxx.se/changes.html#7_60_0

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

package/network/utils/curl/patches/310-mbedtls-disable-runtime-version-check.patch

@@ -6,6 +6,6 @@
  {
 -  unsigned int version = mbedtls_version_get_number();
 +  unsigned int version = MBEDTLS_VERSION_NUMBER;
-   return snprintf(buffer, size, "mbedTLS/%d.%d.%d", version>>24,
+   return snprintf(buffer, size, "mbedTLS/%u.%u.%u", version>>24,
                    (version>>16)&0xff, (version>>8)&0xff);
  }