Add PostPagination component for blog post navigation

src/components/PostPagination.astro

@@ -0,0 +1,47 @@
+---
+const { prevPost, nextPost } = Astro.props;
+---
+
+<style lang="scss">
+	.pagination {
+		overflow: hidden;
+		padding: 5rem 0;
+		width: 100%;
+	}
+
+	@media (width <=684px) {
+		.pagination {
+			padding: 2rem 0;
+		}
+	}
+
+	.prev,
+	.next {
+		max-width: 40%;
+	}
+
+	.prev {
+		float: left;
+	}
+
+	.next {
+		float: right;
+	}
+</style>
+
+<div class="pagination">
+	{
+		prevPost && (
+			<span class="prev">
+				<a href={`/blog/${prevPost.slug}`}>&lt; {prevPost.data.title}</a>
+			</span>
+		)
+	}
+	{
+		nextPost && (
+			<span class="next">
+				<a href={`/blog/${nextPost.slug}`}>{nextPost.data.title} &gt;</a>
+			</span>
+		)
+	}
+</div>