http3: adjust cast for ngtcp2 v0.19.0

ngtcp2 v0.19.0 made size of `ecn` member of `ngtcp2_pkt_info`
an `uint8_t` (was: `uint32_t`). Adjust our local cast accordingly.

Fixes:
```
./curl/lib/vquic/curl_ngtcp2.c:1912:12: warning: implicit conversion loses integer precision: 'uint32_t' (aka 'unsigned int') to 'uint8_t' (aka 'unsigned char') [-Wimplicit-int-conversion]
  pi.ecn = (uint32_t)ecn;
         ~ ^~~~~~~~~~~~~
```

Also bump ngtcp2, nghttp3 and nghttp2 to their latest versions in our
docs and CI.

Ref: 80447281bb
Ref: https://github.com/ngtcp2/ngtcp2/pull/877
Closes #11798

.github/workflows/ngtcp2-linux.yml

@@ -49,9 +49,9 @@ env:
   quictls-version: 3.0.10+quic
   gnutls-version: 3.8.0
   wolfssl-version: master
-  nghttp3-version: v0.14.0
-  ngtcp2-version: v0.18.0
-  nghttp2-version: v1.55.1
+  nghttp3-version: v0.15.0
+  ngtcp2-version: v0.19.0
+  nghttp2-version: v1.56.0
   mod_h2-version: v2.0.21
 
 jobs:

.github/workflows/quiche-linux.yml

@@ -47,9 +47,9 @@ permissions: {}
 env:
   MAKEFLAGS: -j 3
   openssl-version: 3.0.10+quic
-  nghttp3-version: v0.14.0
-  ngtcp2-version: v0.18.0
-  nghttp2-version: v1.55.1
+  nghttp3-version: v0.15.0
+  ngtcp2-version: v0.19.0
+  nghttp2-version: v1.56.0
   quiche-version: 0.17.2
   mod_h2-version: v2.0.21
 

docs/HTTP3.md

@@ -39,8 +39,8 @@ Building curl with ngtcp2 involves 3 components: `ngtcp2` itself, `nghttp3` and
 
 For now, `ngtcp2` and `nghttp3` are still *experimental* which means their evolution bring breaking changes. Therefore, the proper version of both libraries need to be used when building curl. These are
 
- * `ngtcp2`: v0.18.0
- * `nghttp3`: v0.14.0
+ * `ngtcp2`: v0.19.0
+ * `nghttp3`: v0.15.0
 
 ## Build with OpenSSL
 
@@ -55,7 +55,7 @@ Build (patched) OpenSSL
 Build nghttp3
 
      % cd ..
-     % git clone -b v0.14.0 https://github.com/ngtcp2/nghttp3
+     % git clone -b v0.15.0 https://github.com/ngtcp2/nghttp3
      % cd nghttp3
      % autoreconf -fi
      % ./configure --prefix=<somewhere2> --enable-lib-only
@@ -65,7 +65,7 @@ Build nghttp3
 Build ngtcp2
 
      % cd ..
-     % git clone -b v0.18.0 https://github.com/ngtcp2/ngtcp2
+     % git clone -b v0.19.0 https://github.com/ngtcp2/ngtcp2
      % cd ngtcp2
      % autoreconf -fi
      % ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only
@@ -98,7 +98,7 @@ Build GnuTLS
 Build nghttp3
 
      % cd ..
-     % git clone -b v0.14.0 https://github.com/ngtcp2/nghttp3
+     % git clone -b v0.15.0 https://github.com/ngtcp2/nghttp3
      % cd nghttp3
      % autoreconf -fi
      % ./configure --prefix=<somewhere2> --enable-lib-only
@@ -108,7 +108,7 @@ Build nghttp3
 Build ngtcp2
 
      % cd ..
-     % git clone -b v0.18.0 https://github.com/ngtcp2/ngtcp2
+     % git clone -b v0.19.0 https://github.com/ngtcp2/ngtcp2
      % cd ngtcp2
      % autoreconf -fi
      % ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only --with-gnutls
@@ -139,7 +139,7 @@ Build wolfSSL
 Build nghttp3
 
      % cd ..
-     % git clone -b v0.14.0 https://github.com/ngtcp2/nghttp3
+     % git clone -b v0.15.0 https://github.com/ngtcp2/nghttp3
      % cd nghttp3
      % autoreconf -fi
      % ./configure --prefix=<somewhere2> --enable-lib-only
@@ -149,7 +149,7 @@ Build nghttp3
 Build ngtcp2
 
      % cd ..
-     % git clone -b v0.18.0 https://github.com/ngtcp2/ngtcp2
+     % git clone -b v0.19.0 https://github.com/ngtcp2/ngtcp2
      % cd ngtcp2
      % autoreconf -fi
      % ./configure PKG_CONFIG_PATH=<somewhere1>/lib/pkgconfig:<somewhere2>/lib/pkgconfig LDFLAGS="-Wl,-rpath,<somewhere1>/lib" --prefix=<somewhere3> --enable-lib-only --with-wolfssl

lib/vquic/curl_ngtcp2.c

@@ -1919,7 +1919,7 @@ static CURLcode recv_pkt(const unsigned char *pkt, size_t pktlen,
                    ctx->q.local_addrlen);
   ngtcp2_addr_init(&path.remote, (struct sockaddr *)remote_addr,
                    remote_addrlen);
-  pi.ecn = (uint32_t)ecn;
+  pi.ecn = (uint8_t)ecn;
 
   rv = ngtcp2_conn_read_pkt(ctx->qconn, &path, &pi, pkt, pktlen, pktx->ts);
   if(rv) {