[librsvg/wip/dimensions-api] Don't use deprecated str.trim_left() and trim_right()

[Federico Mena Quintero <federico src gnome org>]

commit b5b79e9cd83c9531bbed914b7468ed01f525246e
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Feb 8 20:19:53 2019 -0600

    Don't use deprecated str.trim_left() and trim_right()
    
    Now we use trim_start() and trim_end(), respectively.  This increases
    the minimum Rust version to 1.30.0.

 COMPILING.md                | 2 +-
 NEWS                        | 3 +++
 configure.ac                | 2 +-
 rsvg_internals/src/space.rs | 4 ++--
 4 files changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/COMPILING.md b/COMPILING.md
index 690da92b..0a6ec7f0 100644
--- a/COMPILING.md
+++ b/COMPILING.md
@@ -32,7 +32,7 @@ minimum version is listed here; you may use a newer version instead.
 **Compilers:**
 
 * a C compiler and `make` tool; we recommend GNU `make`.
-* rust 1.27 or later
+* rust 1.30 or later
 * cargo
 
 **Mandatory dependencies:**
diff --git a/NEWS b/NEWS
index d3f0f513..e229c5b9 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,6 @@
+Version 2.45.6
+- Librsvg now requires Rust 1.30.0 or later.
+
 Version 2.45.5
 - At build time, you can now pass $CARGO and $RUSTC environment
   variables if you need to override the default Rust toolchain.
diff --git a/configure.ac b/configure.ac
index 5c2cc458..8e2b34b3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -113,7 +113,7 @@ AS_IF(test x$RUSTC = xno,
 dnl Minimum version of rustc that we support
 dnl If you change this, please update COMPILING.md
 MINIMUM_RUST_MAJOR=1
-MINIMUM_RUST_MINOR=27
+MINIMUM_RUST_MINOR=30
 
 rust_version=`$RUSTC --version`
 version=`echo "$rust_version" | sed -e 's/^rustc //g'`
diff --git a/rsvg_internals/src/space.rs b/rsvg_internals/src/space.rs
index 4350db28..26276f45 100644
--- a/rsvg_internals/src/space.rs
+++ b/rsvg_internals/src/space.rs
@@ -34,11 +34,11 @@ fn normalize_default(elements: NormalizeDefault, s: &str) -> String {
     let mut s = s;
 
     if !elements.has_element_before {
-        s = s.trim_left();
+        s = s.trim_start();
     }
 
     if !elements.has_element_after {
-        s = s.trim_right();
+        s = s.trim_end();
     }
 
     s.chars()