Fix links

Author: joto

_file_formats_manual/05_pbf.md

@@ -4,7 +4,7 @@ title: PBF Format
 ---
 
 The [PBF](https://wiki.openstreetmap.org/wiki/PBF_Format) file format is based
-on the [Google Protocol Buffers](https://developers.google.com/protocol-buffers/).
+on the [Google Protocol Buffers](https://protobuf.dev/).
 PBF files are very space efficient and faster to use than XML files. PBF files
 can contain normal OSM data or OSM history data, but there is no equivalent to
 the XML .osc format.

_libosmium_manual/02_dependencies.md

@@ -106,8 +106,8 @@ You need at least Boost version 1.55.
 
 _Not needed any more from version 2.3.0 onwards_
 
-[Google Protocol Buffers](https://developers.google.com/protocol-buffers/) in
-at least version 2.4.0 is needed for reading and writing [OSM PBF
+[Google Protocol Buffers](https://protobuf.dev/) in at least version 2.4.0 is
+needed for reading and writing [OSM PBF
 files](https://wiki.openstreetmap.org/wiki/PBF_Format).
 
 * Debian/Ubuntu: `libprotobuf-dev`, `protobuf-compiler`
@@ -144,7 +144,7 @@ a version from the git repository.
 
 _Not needed any more from version 2.15.0 onwards_
 
-The [utf8-cpp](http://utfcpp.sourceforge.net/) library is needed for the OPL
+The [utf8-cpp](https://utfcpp.sourceforge.net/) library is needed for the OPL
 output format. A copy of this library is included in the libosmium repository
 but not installed by default. Either use the packages of your distribution,
 install it from the source, or use the `INSTALL_UTFCPP` option of the libosmium

_libosmium_manual/03_building.md

@@ -194,7 +194,7 @@ with `INSTALL_PROTOZERO`. Newer versions of libosmium don't include this any
 more.)
 
 (Libosmium versions 2.14.0 and before also included
-[utfcpp](http://utfcpp.sourceforge.net/) which could be included
+[utfcpp](https://utfcpp.sourceforge.net/) which could be included
 with `INSTALL_UTFCPP`. Newer versions of libosmium don't include this any
 more.)