GHA: bump nghttp2 version to v1.59.0

- Switch to v1.59.0 for GHA CI jobs that use a specific nghttp2-version.

Closes https://github.com/curl/curl/pull/12766

.github/workflows/ngtcp2-linux.yml

@@ -51,7 +51,7 @@ env:
   wolfssl-version: master
   nghttp3-version: v1.1.0
   ngtcp2-version: v1.1.0
-  nghttp2-version: v1.58.0
+  nghttp2-version: v1.59.0
   mod_h2-version: v2.0.25
 
 jobs:

.github/workflows/osslq-linux.yml

@@ -50,7 +50,7 @@ env:
   quictls-version: 3.1.4+quic
   nghttp3-version: v1.1.0
   ngtcp2-version: v1.1.0
-  nghttp2-version: master
+  nghttp2-version: v1.59.0
   mod_h2-version: v2.0.25
 
 jobs:

.github/workflows/quiche-linux.yml

@@ -49,7 +49,7 @@ env:
   openssl-version: 3.1.4+quic
   nghttp3-version: v1.1.0
   ngtcp2-version: v1.1.0
-  nghttp2-version: v1.58.0
+  nghttp2-version: v1.59.0
   quiche-version: 0.19.0
   mod_h2-version: v2.0.25